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-
- -=< The IBM Microchannel SCSI-Subsystem >=-
-
- for the IBM PS/2 series
-
- Low Level Software-Driver for Linux
-
- Copyright (c) 1995 Strom Systems, Inc. under the terms of the GNU
- General Public License. Originally written by Martin Kolinek, December 1995.
- Officially modified and maintained by Michael Lang since January 1999.
-
- Version 4.0a
-
- Last update: January 3, 2001
-
- Before you Start
- ----------------
- This is the common README.ibmmca file for all driver releases of the
- IBM MCA SCSI driver for Linux. Please note, that driver releases 4.0
- or newer do not work with kernel versions older than 2.4.0, while driver
- versions older than 4.0 do not work with kernels 2.4.0 or later! If you
- try to compile your kernel with the wrong driver source, the
- compilation is aborted and you get a corresponding error message. This is
- no bug in the driver; it prevents you from using the wrong source code
- with the wrong kernel version.
-
- Authors of this Driver
- ----------------------
- - Chris Beauregard (improvement of the SCSI-device mapping by the driver)
- - Martin Kolinek (origin, first release of this driver)
- - Klaus Kudielka (multiple SCSI-host management/detection, adaption to
- Linux Kernel 2.1.x, module support)
- - Michael Lang (assigning original pun/lun mapping, dynamical ldn
- assignment, rewritten adapter detection, this file,
- patches, official driver maintenance and subsequent
- debugging, related with the driver)
-
- Table of Contents
- -----------------
- 1 Abstract
- 2 Driver Description
- 2.1 IBM SCSI-Subsystem Detection
- 2.2 Physical Units, Logical Units, and Logical Devices
- 2.3 SCSI-Device Recognition and dynamical ldn Assignment
- 2.4 SCSI-Device Order
- 2.5 Regular SCSI-Command-Processing
- 2.6 Abort & Reset Commands
- 2.7 Disk Geometry
- 2.8 Kernel Boot Option
- 2.9 Driver Module Support
- 2.10 Multiple Hostadapter Support
- 2.11 /proc/scsi-Filesystem Information
- 2.12 /proc/mca-Filesystem Information
- 2.13 Supported IBM SCSI-Subsystems
- 2.14 Linux Kernel Versions
- 3 Code History
- 4 To do
- 5 Users' Manual
- 5.1 Commandline Parameters
- 5.2 Troubleshooting
- 5.3 Bug reports
- 5.4 Support WWW-page
- 6 References
- 7 Credits to
- 7.1 People
- 7.2 Sponsors & Supporters
- 8 Trademarks
- 9 Disclaimer
-
- * * *
-
- 1 Abstract
- ----------
- This README-file describes the IBM SCSI-subsystem low level driver for
- Linux. The descriptions which were formerly kept in the source code have
- been taken out of this file to simplify the codes readability. The driver
- description has been updated, as most of the former description was already
- quite outdated. The history of the driver development is also kept inside
- here. Multiple historical developments have been summarized to shorten the
- text size a bit. At the end of this file you can find a small manual for
- this driver and hints to get it running on your machine.
-
- 2 Driver Description
- --------------------
- 2.1 IBM SCSI-Subsystem Detection
- --------------------------------
- This is done in the ibmmca_detect() function. It first checks, if the
- Microchannel-bus support is enabled, as the IBM SCSI-subsystem needs the
- Microchannel. In a next step, a free interrupt is chosen and the main
- interrupt handler is connected to it to handle answers of the SCSI-
- subsystem(s). If the F/W SCSI-adapter is forced by the BIOS to use IRQ11
- instead of IRQ14, IRQ11 is used for the IBM SCSI-2 F/W adapter. In a
- further step it is checked, if the adapter gets detected by force from
- the kernel commandline, where the I/O port and the SCSI-subsystem id can
- be specified. The next step checks if there is an integrated SCSI-subsystem
- installed. This register area is fixed through all IBM PS/2 MCA-machines
- and appears as something like a virtual slot 10 of the MCA-bus. On most
- PS/2 machines, the POS registers of slot 10 are set to 0xff or 0x00 if not
- integrated SCSI-controller is available. But on certain PS/2s, like model
- 9595, this slot 10 is used to store other information which at earlier
- stage confused the driver and resulted in the detection of some ghost-SCSI.
- If POS-register 2 and 3 are not 0x00 and not 0xff, but all other POS
- registers are either 0xff or 0x00, there must be an integrated SCSI-
- subsystem present and it will be registered as IBM Integrated SCSI-
- Subsystem. The next step checks, if there is a slot-adapter installed on
- the MCA-bus. To get this, the first two POS-registers, that represent the
- adapter ID are checked. If they fit to one of the ids, stored in the
- adapter list, a SCSI-subsystem is assumed to be found in a slot and will be
- registered. This check is done through all possible MCA-bus slots to allow
- more than one SCSI-adapter to be present in the PS/2-system and this is
- already the first point of problems. Looking into the technical reference
- manual for the IBM PS/2 common interfaces, the POS2 register must have
- different interpretation of its single bits to avoid overlapping I/O
- regions. While one can assume, that the integrated subsystem has a fix
- I/O-address at 0x3540 - 0x3547, further installed IBM SCSI-adapters must
- use a different I/O-address. This is expressed by bit 1 to 3 of POS2
- (multiplied by 8 + 0x3540). Bits 2 and 3 are reserved for the integrated
- subsystem, but not for the adapters! The following list shows, how the
- bits of POS2 and POS3 should be interpreted.
-
- The POS2-register of all PS/2 models' integrated SCSI-subsystems has the
- following interpretation of bits:
- Bit 7 - 4 : Chip Revision ID (Release)
- Bit 3 - 2 : Reserved
- Bit 1 : 8k NVRAM Disabled
- Bit 0 : Chip Enable (EN-Signal)
- The POS3-register is interpreted as follows (for most IBM SCSI-subsys.):
- Bit 7 - 5 : SCSI ID
- Bit 4 - 0 : Reserved = 0
- The slot-adapters have different interpretation of these bits. The IBM SCSI
- adapter (w/Cache) and the IBM SCSI-2 F/W adapter use the following
- interpretation of the POS2 register:
- Bit 7 - 4 : ROM Segment Address Select
- Bit 3 - 1 : Adapter I/O Address Select (*8+0x3540)
- Bit 0 : Adapter Enable (EN-Signal)
- and for the POS3 register:
- Bit 7 - 5 : SCSI ID
- Bit 4 : Fairness Enable (SCSI ID3 f. F/W)
- Bit 3 - 0 : Arbitration Level
- The most modern product of the series is the IBM SCSI-2 F/W adapter, it
- allows dual-bus SCSI and SCSI-wide addressing, which means, PUNs may be
- between 0 and 15. Here, Bit 4 is the high-order bit of the 4-bit wide
- adapter PUN expression. In short words, this means, that IBM PS/2 machines
- can only support 1 single integrated subsystem by default. Additional
- slot-adapters get ports assigned by the automatic configuration tool.
-
- One day I found a patch in ibmmca_detect(), forcing the I/O-address to be
- 0x3540 for integrated SCSI-subsystems, there was a remark placed, that on
- integrated IBM SCSI-subsystems of model 56, the POS2 register was showing 5.
- This means, that really for these models, POS2 has to be interpreted
- sticking to the technical reference guide. In this case, the bit 2 (4) is
- a reserved bit and may not be interpreted. These differences between the
- adapters and the integrated controllers are taken into account by the
- detection routine of the driver on from version >3.0g.
-
- Every time, a SCSI-subsystem is discovered, the ibmmca_register() function
- is called. This function checks first, if the requested area for the I/O-
- address of this SCSI-subsystem is still available and assigns this I/O-
- area to the SCSI-subsystem. There are always 8 sequential I/O-addresses
- taken for each individual SCSI-subsystem found, which are:
-
- Offset Type Permissions
- 0 Command Interface Register 1 Read/Write
- 1 Command Interface Register 2 Read/Write
- 2 Command Interface Register 3 Read/Write
- 3 Command Interface Register 4 Read/Write
- 4 Attention Register Read/Write
- 5 Basic Control Register Read/Write
- 6 Interrupt Status Register Read
- 7 Basic Status Register Read
-
- After the I/O-address range is assigned, the host-adapter is assigned
- to a local structure which keeps all adapter information needed for the
- driver itself and the mid- and higher-level SCSI-drivers. The SCSI pun/lun
- and the adapters' ldn tables are initialized and get probed afterwards by
- the check_devices() function. If no further adapters are found,
- ibmmca_detect() quits.
-
- 2.2 Physical Units, Logical Units, and Logical Devices
- ------------------------------------------------------
- There can be up to 56 devices on the SCSI bus (besides the adapter):
- there are up to 7 "physical units" (each identified by physical unit
- number or pun, also called the scsi id, this is the number you select
- with hardware jumpers), and each physical unit can have up to 8
- "logical units" (each identified by logical unit number, or lun,
- between 0 and 7). The IBM SCSI-2 F/W adapter offers this on up to two
- busses and provides support for 30 logical devices at the same time, where
- in wide-addressing mode you can have 16 puns with 32 luns on each device.
- This section describes the handling of devices on non-F/W adapters.
- Just imagine, that you can have 16 * 32 = 512 devices on a F/W adapter
- which means a lot of possible devices for such a small machine.
-
- Typically the adapter has pun=7, so puns of other physical units
- are between 0 and 6(15). On a wide-adapter a pun higher than 7 is
- possible, but is normally not used. Almost all physical units have only
- one logical unit, with lun=0. A CD-ROM jukebox would be an example of a
- physical unit with more than one logical unit.
-
- The embedded microprocessor of the IBM SCSI-subsystem hides the complex
- two-dimensional (pun,lun) organization from the operating system.
- When the machine is powered-up (or rebooted), the embedded microprocessor
- checks, on its own, all 56 possible (pun,lun) combinations, and the first
- 15 devices found are assigned into a one-dimensional array of so-called
- "logical devices", identified by "logical device numbers" or ldn. The last
- ldn=15 is reserved for the subsystem itself. Wide adapters may have
- to check up to 15 * 8 = 120 pun/lun combinations.
-
- 2.3 SCSI-Device Recognition and Dynamical ldn Assignment
- --------------------------------------------------------
- One consequence of information hiding is that the real (pun,lun)
- numbers are also hidden. The two possibilities to get around this problem
- are to offer fake pun/lun combinations to the operating system or to
- delete the whole mapping of the adapter and to reassign the ldns, using
- the immediate assign command of the SCSI-subsystem for probing through
- all possible pun/lun combinations. An ldn is a "logical device number"
- which is used by IBM SCSI-subsystems to access some valid SCSI-device.
- At the beginning of the development of this driver, the following approach
- was used:
-
- First, the driver checked the ldn's (0 to 6) to find out which ldn's
- have devices assigned. This was done by the functions check_devices() and
- device_exists(). The interrupt handler has a special paragraph of code
- (see local_checking_phase_flag) to assist in the checking. Assume, for
- example, that three logical devices were found assigned at ldn 0, 1, 2.
- These are presented to the upper layer of Linux SCSI driver
- as devices with bogus (pun, lun) equal to (0,0), (1,0), (2,0).
- On the other hand, if the upper layer issues a command to device
- say (4,0), this driver returns DID_NO_CONNECT error.
-
- In a second step of the driver development, the following improvement has
- been applied: The first approach limited the number of devices to 7, far
- fewer than the 15 that it could use, then it just mapped ldn ->
- (ldn/8,ldn%8) for pun,lun. We ended up with a real mishmash of puns
- and luns, but it all seemed to work.
-
- The latest development, which is implemented from the driver version 3.0
- and later, realizes the device recognition in the following way:
- The physical SCSI-devices on the SCSI-bus are probed via immediate_assign-
- and device_inquiry-commands, that is all implemented in a completely new
- made check_devices() subroutine. This delivers an exact map of the physical
- SCSI-world that is now stored in the get_scsi[][]-array. This means,
- that the once hidden pun,lun assignment is now known to this driver.
- It no longer believes in default-settings of the subsystem and maps all
- ldns to existing pun,lun "by foot". This assures full control of the ldn
- mapping and allows dynamical remapping of ldns to different pun,lun, if
- there are more SCSI-devices installed than ldns available (n>15). The
- ldns from 0 to 6 get 'hardwired' by this driver to puns 0 to 7 at lun=0,
- excluding the pun of the subsystem. This assures, that at least simple
- SCSI-installations have optimum access-speed and are not touched by
- dynamical remapping. The ldns 7 to 14 are put to existing devices with
- lun>0 or to non-existing devices, in order to satisfy the subsystem, if
- there are less than 15 SCSI-devices connected. In the case of more than 15
- devices, the dynamical mapping goes active. If the get_scsi[][] reports a
- device to be existent, but it has no ldn assigned, it gets an ldn out of 7
- to 14. The numbers are assigned in cyclic order, therefore it takes 8
- dynamical reassignments on the SCSI-devices until a certain device
- loses its ldn again. This assures that dynamical remapping is avoided
- during intense I/O between up to 15 SCSI-devices (means pun,lun
- combinations). A further advantage of this method is that people who
- build their kernel without probing on all luns will get what they expect,
- because the driver just won't assign everything with lun>0 when
- multiple lun probing is inactive.
-
- 2.4 SCSI-Device Order
- ---------------------
- Because of the now correct recognition of physical pun,lun, and
- their report to mid-level- and higher-level-drivers, the new reported puns
- can be different from the old, faked puns. Therefore, Linux will eventually
- change /dev/sdXXX assignments and prompt you for corrupted superblock
- repair on boottime. In this case DO NOT PANIC, YOUR DISKS ARE STILL OK!!!
- You have to reboot (CTRL-D) with an old kernel and set the /etc/fstab-file
- entries right. After that, the system should come up as errorfree as before.
- If your boot-partition is not coming up, also edit the /etc/lilo.conf-file
- in a Linux session booted on old kernel and run lilo before reboot. Check
- lilo.conf anyway to get boot on other partitions with foreign OSes right
- again. But there exists a feature of this driver that allows you to change
- the assignment order of the SCSI-devices by flipping the PUN-assignment.
- See the next paragraph for a description.
-
- The problem for this is, that Linux does not assign the SCSI-devices in the
- way as described in the ANSI-SCSI-standard. Linux assigns /dev/sda to
- the device with at minimum id 0. But the first drive should be at id 6,
- because for historical reasons, drive at id 6 has, by hardware, the highest
- priority and a drive at id 0 the lowest. IBM was one of the rare producers,
- where the BIOS assigns drives belonging to the ANSI-SCSI-standard. Most
- other producers' BIOS does not (I think even Adaptec-BIOS). The
- IBMMCA_SCSI_ORDER_STANDARD flag, which you set while configuring the
- kernel enables to choose the preferred way of SCSI-device-assignment.
- Defining this flag would result in Linux determining the devices in the
- same order as DOS and OS/2 does on your MCA-machine. This is also standard
- on most industrial computers and OSes, like e.g. OS-9. Leaving this flag
- undefined will get your devices ordered in the default way of Linux. See
- also the remarks of Chris Beauregard from Dec 15, 1997 and the followups
- in section 3.
-
- 2.5 Regular SCSI-Command-Processing
- -----------------------------------
- Only three functions get involved: ibmmca_queuecommand(), issue_cmd(),
- and interrupt_handler().
-
- The upper layer issues a scsi command by calling function
- ibmmca_queuecommand(). This function fills a "subsystem control block"
- (scb) and calls a local function issue_cmd(), which writes a scb
- command into subsystem I/O ports. Once the scb command is carried out,
- the interrupt_handler() is invoked. If a device is determined to be
- existent and it has not assigned any ldn, it gets one dynamically.
- For this, the whole stuff is done in ibmmca_queuecommand().
-
- 2.6 Abort & Reset Commands
- --------------------------
- These are implemented with busy waiting for interrupt to arrive.
- ibmmca_reset() and ibmmca_abort() do not work sufficiently well
- up to now and need still a lot of development work. This seems
- to be a problem with other low-level SCSI drivers too, however
- this should be no excuse.
-
- 2.7 Disk Geometry
- -----------------
- The ibmmca_biosparams() function should return the same disk geometry
- as the bios. This is needed for fdisk, etc. The returned geometry is
- certainly correct for disks smaller than 1 gigabyte. In the meantime,
- it has been proved, that this works fine even with disks larger than
- 1 gigabyte.
-
- 2.8 Kernel Boot Option
- ----------------------
- The function ibmmca_scsi_setup() is called if option ibmmcascsi=n
- is passed to the kernel. See file linux/init/main.c for details.
-
- 2.9 Driver Module Support
- -------------------------
- Is implemented and tested by K. Kudielka. This could probably not work
- on kernels <2.1.0.
-
- 2.10 Multiple Hostadapter Support
- ---------------------------------
- This driver supports up to eight interfaces of type IBM-SCSI-Subsystem.
- Integrated-, and MCA-adapters are automatically recognized. Unrecognizable
- IBM-SCSI-Subsystem interfaces can be specified as kernel-parameters.
-
- 2.11 /proc/scsi-Filesystem Information
- --------------------------------------
- Information about the driver condition is given in
- /proc/scsi/ibmmca/<host_no>. ibmmca_proc_info() provides this information.
-
- This table is quite informative for interested users. It shows the load
- of commands on the subsystem and whether you are running the bypassed
- (software) or integrated (hardware) SCSI-command set (see below). The
- amount of accesses is shown. Read, write, modeselect is shown separately
- in order to help debugging problems with CD-ROMs or tapedrives.
-
- The following table shows the list of 15 logical device numbers, that are
- used by the SCSI-subsystem. The load on each ldn is shown in the table,
- again, read and write commands are split. The last column shows the amount
- of reassignments, that have been applied to the ldns, if you have more than
- 15 pun/lun combinations available on the SCSI-bus.
-
- The last two tables show the pun/lun map and the positions of the ldns
- on this pun/lun map. This may change during operation, when a ldn is
- reassigned to another pun/lun combination. If the necessity for dynamical
- assignments is set to 'no', the ldn structure keeps static.
-
- 2.12 /proc/mca-Filesystem Information
- -------------------------------------
- The slot-file contains all default entries and in addition chip and I/O-
- address information of the SCSI-subsystem. This information is provided
- by ibmmca_getinfo().
-
- 2.13 Supported IBM SCSI-Subsystems
- ----------------------------------
- The following IBM SCSI-subsystems are supported by this driver:
-
- - IBM Fast/Wide SCSI-2 Adapter
- - IBM 7568 Industrial Computer SCSI Adapter w/Cache
- - IBM Expansion Unit SCSI Controller
- - IBM SCSI Adapter w/Cache
- - IBM SCSI Adapter
- - IBM Integrated SCSI Controller
- - All clones, 100% compatible with the chipset and subsystem command
- system of IBM SCSI-adapters (forced detection)
-
- 2.14 Linux Kernel Versions
- --------------------------
- The IBM SCSI-subsystem low level driver is prepared to be used with
- all versions of Linux between 2.0.x and 2.4.x. The compatibility checks
- are fully implemented up from version 3.1e of the driver. This means, that
- you just need the latest ibmmca.h and ibmmca.c file and copy it in the
- linux/drivers/scsi directory. The code is automatically adapted during
- kernel compilation. This is different from kernel 2.4.0! Here version
- 4.0 or later of the driver must be used for kernel 2.4.0 or later. Version
- 4.0 or later does not work together with older kernels! Driver versions
- older than 4.0 do not work together with kernel 2.4.0 or later. They work
- on all older kernels.
-
- 3 Code History
- --------------
- Jan 15 1996: First public release.
- - Martin Kolinek
-
- Jan 23 1996: Scrapped code which reassigned scsi devices to logical
- device numbers. Instead, the existing assignment (created
- when the machine is powered-up or rebooted) is used.
- A side effect is that the upper layer of Linux SCSI
- device driver gets bogus scsi ids (this is benign),
- and also the hard disks are ordered under Linux the
- same way as they are under dos (i.e., C: disk is sda,
- D: disk is sdb, etc.).
- - Martin Kolinek
-
- I think that the CD-ROM is now detected only if a CD is
- inside CD_ROM while Linux boots. This can be fixed later,
- once the driver works on all types of PS/2's.
- - Martin Kolinek
-
- Feb 7 1996: Modified biosparam function. Fixed the CD-ROM detection.
- For now, devices other than harddisk and CD_ROM are
- ignored. Temporarily modified abort() function
- to behave like reset().
- - Martin Kolinek
-
- Mar 31 1996: The integrated scsi subsystem is correctly found
- in PS/2 models 56,57, but not in model 76. Therefore
- the ibmmca_scsi_setup() function has been added today.
- This function allows the user to force detection of
- scsi subsystem. The kernel option has format
- ibmmcascsi=n
- where n is the scsi_id (pun) of the subsystem. Most likely, n is 7.
- - Martin Kolinek
-
- Aug 21 1996: Modified the code which maps ldns to (pun,0). It was
- insufficient for those of us with CD-ROM changers.
- - Chris Beauregard
-
- Dec 14 1996: More improvements to the ldn mapping. See check_devices
- for details. Did more fiddling with the integrated SCSI detection,
- but I think it's ultimately hopeless without actually testing the
- model of the machine. The 56, 57, 76 and 95 (ultimedia) all have
- different integrated SCSI register configurations. However, the 56
- and 57 are the only ones that have problems with forced detection.
- - Chris Beauregard
-
- Mar 8-16 1997: Modified driver to run as a module and to support
- multiple adapters. A structure, called ibmmca_hostdata, is now
- present, containing all the variables, that were once only
- available for one single adapter. The find_subsystem-routine has vanished.
- The hardware recognition is now done in ibmmca_detect directly.
- This routine checks for presence of MCA-bus, checks the interrupt
- level and continues with checking the installed hardware.
- Certain PS/2-models do not recognize a SCSI-subsystem automatically.
- Hence, the setup defined by command-line-parameters is checked first.
- Thereafter, the routine probes for an integrated SCSI-subsystem.
- Finally, adapters are checked. This method has the advantage to cover all
- possible combinations of multiple SCSI-subsystems on one MCA-board. Up to
- eight SCSI-subsystems can be recognized and announced to the upper-level
- drivers with this improvement. A set of defines made changes to other
- routines as small as possible.
- - Klaus Kudielka
-
- May 30 1997: (v1.5b)
- 1) SCSI-command capability enlarged by the recognition of MODE_SELECT.
- This needs the RD-Bit to be disabled on IM_OTHER_SCSI_CMD_CMD which
- allows data to be written from the system to the device. It is a
- necessary step to be allowed to set blocksize of SCSI-tape-drives and
- the tape-speed, without confusing the SCSI-Subsystem.
- 2) The recognition of a tape is included in the check_devices routine.
- This is done by checking for TYPE_TAPE, that is already defined in
- the kernel-scsi-environment. The markup of a tape is done in the
- global ldn_is_tape[] array. If the entry on index ldn
- is 1, there is a tapedrive connected.
- 3) The ldn_is_tape[] array is necessary to distinguish between tape- and
- other devices. Fixed blocklength devices should not cause a problem
- with the SCB-command for read and write in the ibmmca_queuecommand
- subroutine. Therefore, I only derivate the READ_XX, WRITE_XX for
- the tape-devices, as recommended by IBM in this Technical Reference,
- mentioned below. (IBM recommends to avoid using the read/write of the
- subsystem, but the fact was, that read/write causes a command error from
- the subsystem and this causes kernel-panic.)
- 4) In addition, I propose to use the ldn instead of a fix char for the
- display of PS2_DISK_LED_ON(). On 95, one can distinguish between the
- devices that are accessed. It shows activity and easyfies debugging.
- The tape-support has been tested with a SONY SDT-5200 and a HP DDS-2
- (I do not know yet the type). Optimization and CD-ROM audio-support,
- I am working on ...
- - Michael Lang
-
- June 19 1997: (v1.6b)
- 1) Submitting the extra-array ldn_is_tape[] -> to the local ld[]
- device-array.
- 2) CD-ROM Audio-Play seems to work now.
- 3) When using DDS-2 (120M) DAT-Tapes, mtst shows still density-code
- 0x13 for ordinary DDS (61000 BPM) instead 0x24 for DDS-2. This appears
- also on Adaptec 2940 adaptor in a PCI-System. Therefore, I assume that
- the problem is independent of the low-level-driver/bus-architecture.
- 4) Hexadecimal ldn on PS/2-95 LED-display.
- 5) Fixing of the PS/2-LED on/off that it works right with tapedrives and
- does not confuse the disk_rw_in_progress counter.
- - Michael Lang
-
- June 21 1997: (v1.7b)
- 1) Adding of a proc_info routine to inform in /proc/scsi/ibmmca/<host> the
- outer-world about operational load statistics on the different ldns,
- seen by the driver. Everybody that has more than one IBM-SCSI should
- test this, because I only have one and cannot see what happens with more
- than one IBM-SCSI hosts.
- 2) Definition of a driver version-number to have a better recognition of
- the source when there are existing too much releases that may confuse
- the user, when reading about release-specific problems. Up to know,
- I calculated the version-number to be 1.7. Because we are in BETA-test
- yet, it is today 1.7b.
- 3) Sorry for the heavy bug I programmed on June 19 1997! After that, the
- CD-ROM did not work any more! The C7-command was a fake impression
- I got while programming. Now, the READ and WRITE commands for CD-ROM are
- no longer running over the subsystem, but just over
- IM_OTHER_SCSI_CMD_CMD. On my observations (PS/2-95), now CD-ROM mounts
- much faster(!) and hopefully all fancy multimedia-functions, like direct
- digital recording from audio-CDs also work. (I tried it with cdda2wav
- from the cdwtools-package and it filled up the harddisk immediately :-).)
- To easify boolean logics, a further local device-type in ld[], called
- is_cdrom has been included.
- 4) If one uses a SCSI-device of unsupported type/commands, one
- immediately runs into a kernel-panic caused by Command Error. To better
- understand which SCSI-command caused the problem, I extended this
- specific panic-message slightly.
- - Michael Lang
-
- June 25 1997: (v1.8b)
- 1) Some cosmetic changes for the handling of SCSI-device-types.
- Now, also CD-Burners / WORMs and SCSI-scanners should work. For
- MO-drives I have no experience, therefore not yet supported.
- In logical_devices I changed from different type-variables to one
- called 'device_type' where the values, corresponding to scsi.h,
- of a SCSI-device are stored.
- 2) There existed a small bug, that maps a device, coming after a SCSI-tape
- wrong. Therefore, e.g. a CD-ROM changer would have been mapped wrong
- -> problem removed.
- 3) Extension of the logical_device structure. Now it contains also device,
- vendor and revision-level of a SCSI-device for internal usage.
- - Michael Lang
-
- June 26-29 1997: (v2.0b)
- 1) The release number 2.0b is necessary because of the completely new done
- recognition and handling of SCSI-devices with the adapter. As I got
- from Chris the hint, that the subsystem can reassign ldns dynamically,
- I remembered this immediate_assign-command, I found once in the handbook.
- Now, the driver first kills all ldn assignments that are set by default
- on the SCSI-subsystem. After that, it probes on all puns and luns for
- devices by going through all combinations with immediate_assign and
- probing for devices, using device_inquiry. The found physical(!) pun,lun
- structure is stored in get_scsi[][] as device types. This is followed
- by the assignment of all ldns to existing SCSI-devices. If more ldns
- than devices are available, they are assigned to non existing pun,lun
- combinations to satisfy the adapter. With this, the dynamical mapping
- was possible to implement. (For further info see the text in the
- source code and in the description below. Read the description
- below BEFORE installing this driver on your system!)
- 2) Changed the name IBMMCA_DRIVER_VERSION to IBMMCA_SCSI_DRIVER_VERSION.
- 3) The LED-display shows on PS/2-95 no longer the ldn, but the SCSI-ID
- (pun) of the accessed SCSI-device. This is now senseful, because the
- pun known within the driver is exactly the pun of the physical device
- and no longer a fake one.
- 4) The /proc/scsi/ibmmca/<host_no> consists now of the first part, where
- hit-statistics of ldns is shown and a second part, where the maps of
- physical and logical SCSI-devices are displayed. This could be very
- interesting, when one is using more than 15 SCSI-devices in order to
- follow the dynamical remapping of ldns.
- - Michael Lang
-
- June 26-29 1997: (v2.0b-1)
- 1) I forgot to switch the local_checking_phase_flag to 1 and back to 0
- in the dynamical remapping part in ibmmca_queuecommand for the
- device_exist routine. Sorry.
- - Michael Lang
-
- July 1-13 1997: (v3.0b,c)
- 1) Merging of the driver-developments of Klaus Kudielka and Michael Lang
- in order to get a optimum and unified driver-release for the
- IBM-SCSI-Subsystem-Adapter(s).
- For people, using the Kernel-release >=2.1.0, module-support should
- be no problem. For users, running under <2.1.0, module-support may not
- work, because the methods have changed between 2.0.x and 2.1.x.
- 2) Added some more effective statistics for /proc-output.
- 3) Change typecasting at necessary points from (unsigned long) to
- virt_to_bus().
- 4) Included #if... at special points to have specific adaption of the
- driver to kernel 2.0.x and 2.1.x. It should therefore also run with
- later releases.
- 5) Magneto-Optical drives and medium-changers are also recognized, now.
- Therefore, we have a completely gapfree recognition of all SCSI-
- device-types, that are known by Linux up to kernel 2.1.31.
- 6) The flag SCSI_IBMMCA_DEV_RESET has been inserted. If it is set within
- the configuration, each connected SCSI-device will get a reset command
- during boottime. This can be necessary for some special SCSI-devices.
- This flag should be included in Config.in.
- (See also the new Config.in file.)
- Probable next improvement: bad disk handler.
- - Michael Lang
-
- Sept 14 1997: (v3.0c)
- 1) Some debugging and speed optimization applied.
- - Michael Lang
-
- Dec 15, 1997
- - chrisb@truespectra.com
- - made the front panel display thingy optional, specified from the
- command-line via ibmmcascsi=display. Along the lines of the /LED
- option for the OS/2 driver.
- - fixed small bug in the LED display that would hang some machines.
- - reversed ordering of the drives (using the
- IBMMCA_SCSI_ORDER_STANDARD define). This is necessary for two main
- reasons:
- - users who've already installed Linux won't be screwed. Keep
- in mind that not everyone is a kernel hacker.
- - be consistent with the BIOS ordering of the drives. In the
- BIOS, id 6 is C:, id 0 might be D:. With this scheme, they'd be
- backwards. This confuses the crap out of those heathens who've
- got a impure Linux installation (which, <wince>, I'm one of).
- This whole problem arises because IBM is actually non-standard with
- the id to BIOS mappings. You'll find, in fdomain.c, a similar
- comment about a few FD BIOS revisions. The Linux (and apparently
- industry) standard is that C: maps to scsi id (0,0). Let's stick
- with that standard.
- - Since this is technically a branch of my own, I changed the
- version number to 3.0e-cpb.
-
- Jan 17, 1998: (v3.0f)
- 1) Addition of some statistical info for /proc in proc_info.
- 2) Taking care of the SCSI-assignment problem, dealed by Chris at Dec 15
- 1997. In fact, IBM is right, concerning the assignment of SCSI-devices
- to driveletters. It is conform to the ANSI-definition of the SCSI-
- standard to assign drive C: to SCSI-id 6, because it is the highest
- hardware priority after the hostadapter (that has still today by
- default everywhere id 7). Also realtime-operating systems that I use,
- like LynxOS and OS9, which are quite industrial systems use top-down
- numbering of the harddisks, that is also starting at id 6. Now, one
- sits a bit between two chairs. On one hand side, using the define
- IBMMCA_SCSI_ORDER_STANDARD makes Linux assigning disks conform to
- the IBM- and ANSI-SCSI-standard and keeps this driver downward
- compatible to older releases, on the other hand side, people is quite
- habituated in believing that C: is assigned to (0,0) and much other
- SCSI-BIOS do so. Therefore, I moved the IBMMCA_SCSI_ORDER_STANDARD
- define out of the driver and put it into Config.in as subitem of
- 'IBM SCSI support'. A help, added to Documentation/Configure.help
- explains the differences between saying 'y' or 'n' to the user, when
- IBMMCA_SCSI_ORDER_STANDARD prompts, so the ordinary user is enabled to
- choose the way of assignment, depending on his own situation and gusto.
- 3) Adapted SCSI_IBMMCA_DEV_RESET to the local naming convention, so it is
- now called IBMMCA_SCSI_DEV_RESET.
- 4) Optimization of proc_info and its subroutines.
- 5) Added more in-source-comments and extended the driver description by
- some explanation about the SCSI-device-assignment problem.
- - Michael Lang
-
- Jan 18, 1998: (v3.0g)
- 1) Correcting names to be absolutely conform to the later 2.1.x releases.
- This is necessary for
- IBMMCA_SCSI_DEV_RESET -> CONFIG_IBMMCA_SCSI_DEV_RESET
- IBMMCA_SCSI_ORDER_STANDARD -> CONFIG_IBMMCA_SCSI_ORDER_STANDARD
- - Michael Lang
-
- Jan 18, 1999: (v3.1 MCA-team internal)
- 1) The multiple hosts structure is accessed from every subroutine, so there
- is no longer the address of the device structure passed from function
- to function, but only the hostindex. A call by value, nothing more. This
- should really be understood by the compiler and the subsystem should get
- the right values and addresses.
- 2) The SCSI-subsystem detection was not complete and quite hugely buggy up
- to now, compared to the technical manual. The interpretation of the pos2
- register is not as assumed by people before, therefore, I dropped a note
- in the ibmmca_detect function to show the registers' interpretation.
- The pos-registers of integrated SCSI-subsystems do not contain any
- information concerning the IO-port offset, really. Instead, they contain
- some info about the adapter, the chip, the NVRAM .... The I/O-port is
- fixed to 0x3540 - 0x3547. There can be more than one adapters in the
- slots and they get an offset for the I/O area in order to get their own
- I/O-address area. See chapter 2 for detailed description. At least, the
- detection should now work right, even on models other than 95. The 95ers
- came happily around the bug, as their pos2 register contains always 0
- in the critical area. Reserved bits are not allowed to be interpreted,
- therefore, IBM is allowed to set those bits as they like and they may
- really vary between different PS/2 models. So, now, no interpretation
- of reserved bits - hopefully no trouble here anymore.
- 3) The command error, which you may get on models 55, 56, 57, 70, 77 and
- P70 may have been caused by the fact, that adapters of older design do
- not like sending commands to non-existing SCSI-devices and will react
- with a command error as a sign of protest. While this error is not
- present on IBM SCSI Adapter w/cache, it appears on IBM Integrated SCSI
- Adapters. Therefore, I implemented a workaround to forgive those
- adapters their protests, but it is marked up in the statistics, so
- after a successful boot, you can see in /proc/scsi/ibmmca/<host_number>
- how often the command errors have been forgiven to the SCSI-subsystem.
- If the number is bigger than 0, you have a SCSI subsystem of older
- design, what should no longer matter.
- 4) ibmmca_getinfo() has been adapted very carefully, so it shows in the
- slotn file really, what is senseful to be presented.
- 5) ibmmca_register() has been extended in its parameter list in order to
- pass the right name of the SCSI-adapter to Linux.
- - Michael Lang
-
- Feb 6, 1999: (v3.1)
- 1) Finally, after some 3.1Beta-releases, the 3.1 release. Sorry, for
- the delayed release, but it was not finished with the release of
- Kernel 2.2.0.
- - Michael Lang
-
- Feb 10, 1999 (v3.1)
- 1) Added a new commandline parameter called 'bypass' in order to bypass
- every integrated subsystem SCSI-command consequently in case of
- troubles.
- 2) Concatenated read_capacity requests to the harddisks. It gave a lot
- of troubles with some controllers and after I wanted to apply some
- extensions, it jumped out in the same situation, on my w/cache, as like
- on D. Weinehalls' Model 56, having integrated SCSI. This gave me the
- decisive hint to move the code-part out and declare it global. Now
- it seems to work far better and more stable. Let us see what
- the world thinks of it...
- 3) By the way, only Sony DAT-drives seem to show density code 0x13. A
- test with a HP drive gave right results, so the problem is vendor-
- specific and not a problem of the OS or the driver.
- - Michael Lang
-
- Feb 18, 1999 (v3.1d)
- 1) The abort command and the reset function have been checked for
- inconsistencies. From the logical point of thinking, they work
- at their optimum, now, but as the subsystem does not answer with an
- interrupt, abort never finishes, sigh...
- 2) Everything, that is accessed by a busmaster request from the adapter
- is now declared as global variable, even the return-buffer in the
- local checking phase. This assures, that no accesses to undefined memory
- areas are performed.
- 3) In ibmmca.h, the line unchecked_isa_dma is added with 1 in order to
- avoid memory-pointers for the areas higher than 16MByte in order to
- be sure, it also works on 16-Bit Microchannel bus systems.
- 4) A lot of small things have been found, but nothing that endangered the
- driver operations. Just it should be more stable, now.
- - Michael Lang
-
- Feb 20, 1999 (v3.1e)
- 1) I took the warning from the Linux Kernel Hackers Guide serious and
- checked the cmd->result return value to the done-function very carefully.
- It is obvious, that the IBM SCSI only delivers the tsb.dev_status, if
- some error appeared, else it is undefined. Now, this is fixed. Before
- any SCB command gets queued, the tsb.dev_status is set to 0, so the
- cmd->result won't screw up Linux higher level drivers.
- 2) The reset-function has slightly improved. This is still planned for
- abort. During the abort and the reset function, no interrupts are
- allowed. This is however quite hard to cope with, so the INT-status
- register is read. When the interrupt gets queued, one can find its
- status immediately on that register and is enabled to continue in the
- reset function. I had no chance to test this really, only in a bogus
- situation, I got this function running, but the situation was too much
- worse for Linux :-(, so tests will continue.
- 3) Buffers got now consistent. No open address mapping, as before and
- therefore no further troubles with the unassigned memory segmentation
- faults that scrambled probes on 95XX series and even on 85XX series,
- when the kernel is done in a not so perfectly fitting way.
- 4) Spontaneous interrupts from the subsystem, appearing without any
- command previously queued are answered with a DID_BAD_INTR result.
- 5) Taken into account ZP Gus' proposals to reverse the SCSI-device
- scan order. As it does not work on Kernel 2.1.x or 2.2.x, as proposed
- by him, I implemented it in a slightly derived way, which offers in
- addition more flexibility.
- - Michael Lang
-
- Apr 23, 2000 (v3.2pre1)
- 1) During a very long time, I collected a huge amount of bug reports from
- various people, trying really quite different things on their SCSI-
- PS/2s. Today, all these bug reports are taken into account and should be
- mostly solved. The major topics were:
- - Driver crashes during boottime by no obvious reason.
- - Driver panics while the midlevel-SCSI-driver is trying to inquire
- the SCSI-device properties, even though hardware is in perfect state.
- - Displayed info for the various slot-cards is interpreted wrong.
- The main reasons for the crashes were two:
- 1) The commands to check for device information like INQUIRY,
- TEST_UNIT_READY, REQUEST_SENSE and MODE_SENSE cause the devices
- to deliver information of up to 255 bytes. Midlevel drivers offer
- 1024 bytes of space for the answer, but the IBM-SCSI-adapters do
- not accept this, as they stick quite near to ANSI-SCSI and report
- a COMMAND_ERROR message which causes the driver to panic. The main
- problem was located around the INQUIRY command. Now, for all the
- mentioned commands, the buffersize sent to the adapter is at
- maximum 255 which seems to be a quite reasonable solution.
- TEST_UNIT_READY gets a buffersize of 0 to make sure that no
- data is transferred in order to avoid any possible command failure.
- 2) On unsuccessful TEST_UNIT_READY, the mid-level driver has to send
- a REQUEST_SENSE in order to see where the problem is located. This
- REQUEST_SENSE may have various length in its answer-buffer. IBM
- SCSI-subsystems report a command failure if the returned buffersize
- is different from the sent buffersize, but this can be suppressed by
- a special bit, which is now done and problems seem to be solved.
- 2) Code adaption to all kernel-releases. Now, the 3.2 code compiles on
- 2.0.x, 2.1.x, 2.2.x and 2.3.x kernel releases without any code-changes.
- 3) Commandline-parameters are recognized again, even under Kernel 2.3.x or
- higher.
- - Michael Lang
-
- April 27, 2000 (v3.2pre2)
- 1) Bypassed commands get read by the adapter by one cycle instead of two.
- This increases SCSI-performance.
- 2) Synchronous datatransfer is provided for sure to be 5 MHz on older
- SCSI and 10 MHz on internal F/W SCSI-adapter.
- 3) New commandline parameters allow to force the adapter to slow down while
- in synchronous transfer. Could be helpful for very old devices.
- - Michael Lang
-
- June 2, 2000 (v3.2pre5)
- 1) Added Jim Shorney's contribution to make the activity indicator
- flashing in addition to the LED-alphanumeric display-panel on
- models 95A. To be enabled to choose this feature freely, a new
- commandline parameter is added, called 'activity'.
- 2) Added the READ_CONTROL bit for test_unit_ready SCSI-command.
- 3) Added some suppress_exception bits to read_device_capacity and
- all device_inquiry occurrences in the driver code.
- 4) Complaints about the various KERNEL_VERSION implementations are
- taken into account. Every local_LinuxKernelVersion occurrence is
- now replaced by KERNEL_VERSION, defined in linux/version.h.
- Corresponding changes were applied to ibmmca.h, too. This was a
- contribution to all kernel-parts by Philipp Hahn.
- - Michael Lang
-
- July 17, 2000 (v3.2pre8)
- A long period of collecting bug reports from all corners of the world
- now lead to the following corrections to the code:
- 1) SCSI-2 F/W support crashed with a COMMAND ERROR. The reason for this
- was that it is possible to disable Fast-SCSI for the external bus.
- The feature-control command, where this crash appeared regularly, tried
- to set the maximum speed of 10MHz synchronous transfer speed and that
- reports a COMMAND ERROR if external bus Fast-SCSI is disabled. Now,
- the feature-command probes down from maximum speed until the adapter
- stops to complain, which is at the same time the maximum possible
- speed selected in the reference program. So, F/W external can run at
- 5 MHz (slow-) or 10 MHz (fast-SCSI). During feature probing, the
- COMMAND ERROR message is used to detect if the adapter does not complain.
- 2) Up to now, only combined busmode is supported, if you use external
- SCSI-devices, attached to the F/W-controller. If dual bus is selected,
- only the internal SCSI-devices get accessed by Linux. For most
- applications, this should do fine.
- 3) Wide-SCSI-addressing (16-Bit) is now possible for the internal F/W
- bus on the F/W adapter. If F/W adapter is detected, the driver
- automatically uses the extended PUN/LUN <-> LDN mapping tables, which
- are now new from 3.2pre8. This allows PUNs between 0 and 15 and should
- provide more fun with the F/W adapter.
- 4) Several machines use the SCSI: POS registers for internal/undocumented
- storage of system relevant info. This confused the driver, mainly on
- models 9595, as it expected no onboard SCSI only, if all POS in
- the integrated SCSI-area are set to 0x00 or 0xff. Now, the mechanism
- to check for integrated SCSI is much more restrictive and these problems
- should be history.
- - Michael Lang
-
- July 18, 2000 (v3.2pre9)
- This develop rather quickly at the moment. Two major things were still
- missing in 3.2pre8:
- 1) The adapter PUN for F/W adapters has 4-bits, while all other adapters
- have 3-bits. This is now taken into account for F/W.
- 2) When you select CONFIG_IBMMCA_SCSI_ORDER_STANDARD, you should
- normally get the inverse probing order of your devices on the SCSI-bus.
- The ANSI device order gets scrambled in version 3.2pre8!! Now, a new
- and tested algorithm inverts the device-order on the SCSI-bus and
- automatically avoids accidental access to whatever SCSI PUN the adapter
- is set and works with SCSI- and Wide-SCSI-addressing.
- - Michael Lang
-
- July 23, 2000 (v3.2pre10 unpublished)
- 1) LED panel display supports wide-addressing in ibmmca=display mode.
- 2) Adapter-information and autoadaption to address-space is done.
- 3) Auto-probing for maximum synchronous SCSI transfer rate is working.
- 4) Optimization to some embedded function calls is applied.
- 5) Added some comment for the user to wait for SCSI-devices being probed.
- 6) Finished version 3.2 for Kernel 2.4.0. It least, I thought it is but...
- - Michael Lang
-
- July 26, 2000 (v3.2pre11)
- 1) I passed a horrible weekend getting mad with NMIs on kernel 2.2.14 and
- a model 9595. Asking around in the community, nobody except of me has
- seen such errors. Weird, but I am trying to recompile everything on
- the model 9595. Maybe, as I use a specially modified gcc, that could
- cause problems. But, it was not the reason. The true background was,
- that the kernel was compiled for i386 and the 9595 has a 486DX-2.
- Normally, no troubles should appear, but for this special machine,
- only the right processor support is working fine!
- 2) Previous problems with synchronous speed, slowing down from one adapter
- to the next during probing are corrected. Now, local variables store
- the synchronous bitmask for every single adapter found on the MCA bus.
- 3) LED alphanumeric panel support for XX95 systems is now showing some
- alive rotator during boottime. This makes sense, when no monitor is
- connected to the system. You can get rid of all display activity, if
- you do not use any parameter or just ibmmcascsi=activity, for the
- harddrive activity LED, existent on all PS/2, except models 8595-XXX.
- If no monitor is available, please use ibmmcascsi=display, which works
- fine together with the linuxinfo utility for the LED-panel.
- - Michael Lang
-
- July 29, 2000 (v3.2)
- 1) Submission of this driver for kernel 2.4test-XX and 2.2.17.
- - Michael Lang
-
- December 28, 2000 (v3.2d / v4.0)
- 1) The interrupt handler had some wrong statement to wait for. This
- was done due to experimental reasons during 3.2 development but it
- has shown that this is not stable enough. Going back to wait for the
- adapter to be not busy is best.
- 2) Inquiry requests can be shorter than 255 bytes of return buffer. Due
- to a bug in the ibmmca_queuecommand routine, this buffer was forced
- to 255 at minimum. If the memory address, this return buffer is pointing
- to does not offer more space, invalid memory accesses destabilized the
- kernel.
- 3) version 4.0 is only valid for kernel 2.4.0 or later. This is necessary
- to remove old kernel version dependent waste from the driver. 3.2d is
- only distributed with older kernels but keeps compatibility with older
- kernel versions. 4.0 and higher versions cannot be used with older
- kernels anymore!! You must have at least kernel 2.4.0!!
- 4) The commandline argument 'bypass' and all its functionality got removed
- in version 4.0. This was never really necessary, as all troubles were
- based on non-command related reasons up to now, so bypassing commands
- did not help to avoid any bugs. It is kept in 3.2X for debugging reasons.
- 5) Dynamic reassignment of ldns was again verified and analyzed to be
- completely inoperational. This is corrected and should work now.
- 6) All commands that get sent to the SCSI adapter were verified and
- completed in such a way, that they are now completely conform to the
- demands in the technical description of IBM. Main candidates were the
- DEVICE_INQUIRY, REQUEST_SENSE and DEVICE_CAPACITY commands. They must
- be transferred by bypassing the internal command buffer of the adapter
- or else the response can be a random result. GET_POS_INFO would be more
- safe in usage, if one could use the SUPRESS_EXCEPTION_SHORT, but this
- is not allowed by the technical references of IBM. (Sorry, folks, the
- model 80 problem is still a task to be solved in a different way.)
- 7) v3.2d is still hold back for some days for testing, while 4.0 is
- released.
- - Michael Lang
-
- January 3, 2001 (v4.0a)
- 1) A lot of complains after the 2.4.0-prerelease kernel came in about
- the impossibility to compile the driver as a module. This problem is
- solved. In combination with that problem, some unprecise declaration
- of the function option_setup() gave some warnings during compilation.
- This is solved, too by a forward declaration in ibmmca.c.
- 2) #ifdef argument concerning CONFIG_SCSI_IBMMCA is no longer needed and
- was entirely removed.
- 3) Some switch statements got optimized in code, as some minor variables
- in internal SCSI-command handlers.
- - Michael Lang
-
- 4 To do
- -------
- - IBM SCSI-2 F/W external SCSI bus support in separate mode!
- - It seems that the handling of bad disks is really bad -
- non-existent, in fact. However, a low-level driver cannot help
- much, if such things happen.
-
- 5 Users' Manual
- ---------------
- 5.1 Commandline Parameters
- --------------------------
- There exist several features for the IBM SCSI-subsystem driver.
- The commandline parameter format is:
-
- ibmmcascsi=<command1>,<command2>,<command3>,...
-
- where commandN can be one of the following:
-
- display Owners of a model 95 or other PS/2 systems with an
- alphanumeric LED display may set this to have their
- display showing the following output of the 8 digits:
-
- ------DA
-
- where '-' stays dark, 'D' shows the SCSI-device id
- and 'A' shows the SCSI hostindex, being currently
- accessed. During boottime, this will give the message
-
- SCSIini*
-
- on the LED-panel, where the * represents a rotator,
- showing the activity during the probing phase of the
- driver which can take up to two minutes per SCSI-adapter.
- adisplay This works like display, but gives more optical overview
- of the activities on the SCSI-bus. The display will have
- the following output:
-
- 6543210A
-
- where the numbers 0 to 6 light up at the shown position,
- when the SCSI-device is accessed. 'A' shows again the SCSI
- hostindex. If display nor adisplay is set, the internal
- PS/2 harddisk LED is used for media-activities. So, if
- you really do not have a system with a LED-display, you
- should not set display or adisplay. Keep in mind, that
- display and adisplay can only be used alternatively. It
- is not recommended to use this option, if you have some
- wide-addressed devices e.g. at the SCSI-2 F/W adapter in
- your system. In addition, the usage of the display for
- other tasks in parallel, like the linuxinfo-utility makes
- no sense with this option.
- activity This enables the PS/2 harddisk LED activity indicator.
- Most PS/2 have no alphanumeric LED display, but some
- indicator. So you should use this parameter to activate it.
- If you own model 9595 (Server95), you can have both, the
- LED panel and the activity indicator in parallel. However,
- some PS/2s, like the 8595 do not have any harddisk LED
- activity indicator, which means, that you must use the
- alphanumeric LED display if you want to monitor SCSI-
- activity.
- bypass This is obsolete from driver version 4.0, as the adapters
- got that far understood, that the selection between
- integrated and bypassed commands should now work completely
- correct! For historical reasons, the old description is
- kept here:
- This commandline parameter forces the driver never to use
- SCSI-subsystems' integrated SCSI-command set. Except of
- the immediate assign, which is of vital importance for
- every IBM SCSI-subsystem to set its ldns right. Instead,
- the ordinary ANSI-SCSI-commands are used and passed by the
- controller to the SCSI-devices, therefore 'bypass'. The
- effort, done by the subsystem is quite bogus and at a
- minimum and therefore it should work everywhere. This
- could maybe solve troubles with old or integrated SCSI-
- controllers and nasty harddisks. Keep in mind, that using
- this flag will slow-down SCSI-accesses slightly, as the
- software generated commands are always slower than the
- hardware. Non-harddisk devices always get read/write-
- commands in bypass mode. On the most recent releases of
- the Linux IBM-SCSI-driver, the bypass command should be
- no longer a necessary thing, if you are sure about your
- SCSI-hardware!
- normal This is the parameter, introduced on the 2.0.x development
- rail by ZP Gu. This parameter defines the SCSI-device
- scan order in the new industry standard. This means, that
- the first SCSI-device is the one with the lowest pun.
- E.g. harddisk at pun=0 is scanned before harddisk at
- pun=6, which means, that harddisk at pun=0 gets sda
- and the one at pun=6 gets sdb.
- ansi The ANSI-standard for the right scan order, as done by
- IBM, Microware and Microsoft, scans SCSI-devices starting
- at the highest pun, which means, that e.g. harddisk at
- pun=6 gets sda and a harddisk at pun=0 gets sdb. If you
- like to have the same SCSI-device order, as in DOS, OS-9
- or OS/2, just use this parameter.
- fast SCSI-I/O in synchronous mode is done at 5 MHz for IBM-
- SCSI-devices. SCSI-2 Fast/Wide Adapter/A external bus
- should then run at 10 MHz if Fast-SCSI is enabled,
- and at 5 MHz if Fast-SCSI is disabled on the external
- bus. This is the default setting when nothing is
- specified here.
- medium Synchronous rate is at 50% approximately, which means
- 2.5 MHz for IBM SCSI-adapters and 5.0 MHz for F/W ext.
- SCSI-bus (when Fast-SCSI speed enabled on external bus).
- slow The slowest possible synchronous transfer rate is set.
- This means 1.82 MHz for IBM SCSI-adapters and 2.0 MHz
- for F/W external bus at Fast-SCSI speed on the external
- bus.
-
- A further option is that you can force the SCSI-driver to accept a SCSI-
- subsystem at a certain I/O-address with a predefined adapter PUN. This
- is done by entering
-
- commandN = I/O-base
- commandN+1 = adapter PUN
-
- e.g. ibmmcascsi=0x3540,7 will force the driver to detect a SCSI-subsystem
- at I/O-address 0x3540 with adapter PUN 7. Please only use this method, if
- the driver does really not recognize your SCSI-adapter! With driver version
- 3.2, this recognition of various adapters was hugely improved and you
- should try first to remove your commandline arguments of such type with a
- newer driver. I bet, it will be recognized correctly. Even multiple and
- different types of IBM SCSI-adapters should be recognized correctly, too.
- Use the forced detection method only as last solution!
-
- Examples:
-
- ibmmcascsi=adisplay
-
- This will use the advanced display mode for the model 95 LED alphanumeric
- display.
-
- ibmmcascsi=display,0x3558,7
-
- This will activate the default display mode for the model 95 LED display
- and will force the driver to accept a SCSI-subsystem at I/O-base 0x3558
- with adapter PUN 7.
-
- 5.2 Troubleshooting
- -------------------
- The following FAQs should help you to solve some major problems with this
- driver.
-
- Q: "Reset SCSI-devices at boottime" halts the system at boottime, why?
- A: This is only tested with the IBM SCSI Adapter w/cache. It is not
- yet proven to run on other adapters, however you may be lucky.
- In version 3.1d this has been hugely improved and should work better,
- now. Normally you really won't need to activate this flag in the
- kernel configuration, as all post 1989 SCSI-devices should accept
- the reset-signal, when the computer is switched on. The SCSI-
- subsystem generates this reset while being initialized. This flag
- is really reserved for users with very old, very strange or self-made
- SCSI-devices.
- Q: Why is the SCSI-order of my drives mirrored to the device-order
- seen from OS/2 or DOS ?
- A: It depends on the operating system, if it looks at the devices in
- ANSI-SCSI-standard (starting from pun 6 and going down to pun 0) or
- if it just starts at pun 0 and counts up. If you want to be conform
- with OS/2 and DOS, you have to activate this flag in the kernel
- configuration or you should set 'ansi' as parameter for the kernel.
- The parameter 'normal' sets the new industry standard, starting
- from pun 0, scanning up to pun 6. This allows you to change your
- opinion still after having already compiled the kernel.
- Q: Why can't I find IBM MCA SCSI support in the config menu?
- A: You have to activate MCA bus support, first.
- Q: Where can I find the latest info about this driver?
- A: See the file MAINTAINERS for the current WWW-address, which offers
- updates, info and Q/A lists. At this file's origin, the webaddress
- was: http://www.staff.uni-mainz.de/mlang/linux.html
- Q: My SCSI-adapter is not recognized by the driver, what can I do?
- A: Just force it to be recognized by kernel parameters. See section 5.1.
- If this really happens, do also send e-mail to the maintainer, as
- forced detection should be never necessary. Forced detection is in
- principal some flaw of the driver adapter detection and goes into
- bug reports.
- Q: The driver screws up, if it starts to probe SCSI-devices, is there
- some way out of it?
- A: Yes, that was some recognition problem of the correct SCSI-adapter
- and its I/O base addresses. Upgrade your driver to the latest release
- and it should be fine again.
- Q: I get a message: panic IBM MCA SCSI: command error .... , what can
- I do against this?
- A: Previously, I followed the way by ignoring command errors by using
- ibmmcascsi=forgiveall, but this command no longer exists and is
- obsolete. If such a problem appears, it is caused by some segmentation
- fault of the driver, which maps to some unallowed area. The latest
- version of the driver should be ok, as most bugs have been solved.
- Q: There are still kernel panics, even after having set
- ibmmcascsi=forgiveall. Are there other possibilities to prevent
- such panics?
- A: No, get just the latest release of the driver and it should work
- better and better with increasing version number. Forget about this
- ibmmcascsi=forgiveall, as also ignorecmd are obsolete.!
- Q: Linux panics or stops without any comment, but it is probable, that my
- harddisk(s) have bad blocks.
- A: Sorry, the bad-block handling is still a feeble point of this driver,
- but is on the schedule for development in the near future.
- Q: Linux panics while dynamically assigning SCSI-ids or ldns.
- A: If you disconnect a SCSI-device from the machine, while Linux is up
- and the driver uses dynamical reassignment of logical device numbers
- (ldn), it really gets "angry" if it won't find devices, that were still
- present at boottime and stops Linux.
- Q: The system does not recover after an abort-command has been generated.
- A: This is regrettably true, as it is not yet understood, why the
- SCSI-adapter does really NOT generate any interrupt at the end of
- the abort-command. As no interrupt is generated, the abort command
- cannot get finished and the system hangs, sorry, but checks are
- running to hunt down this problem. If there is a real pending command,
- the interrupt MUST get generated after abort. In this case, it
- should finish well.
- Q: The system gets in bad shape after a SCSI-reset, is this known?
- A: Yes, as there are a lot of prescriptions (see the Linux Hackers'
- Guide) what has to be done for reset, we still share the bad shape of
- the reset functions with all other low level SCSI-drivers.
- Astonishingly, reset works in most cases quite ok, but the harddisks
- won't run in synchronous mode anymore after a reset, until you reboot.
- Q: Why does my XXX w/Cache adapter not use read-prefetch?
- A: Ok, that is not completely possible. If a cache is present, the
- adapter tries to use it internally. Explicitly, one can use the cache
- with a read prefetch command, maybe in future, but this requires
- some major overhead of SCSI-commands that risks the performance to
- go down more than it gets improved. Tests with that are running.
- Q: I have a IBM SCSI-2 Fast/Wide adapter, it boots in some way and hangs.
- A: Yes, that is understood, as for sure, your SCSI-2 Fast/Wide adapter
- was in such a case recognized as integrated SCSI-adapter or something
- else, but not as the correct adapter. As the I/O-ports get assigned
- wrongly by that reason, the system should crash in most cases. You
- should upgrade to the latest release of the SCSI-driver. The
- recommended version is 3.2 or later. Here, the F/W support is in
- a stable and reliable condition. Wide-addressing is in addition
- supported.
- Q: I get an Oops message and something like "killing interrupt".
- A: The reason for this is that the IBM SCSI-subsystem only sends a
- termination status back, if some error appeared. In former releases
- of the driver, it was not checked, if the termination status block
- is NULL. From version 3.2, it is taken care of this.
- Q: I have a F/W adapter and the driver sees my internal SCSI-devices,
- but ignores the external ones.
- A: Select combined busmode in the IBM config-program and check for that
- no SCSI-id on the external devices appears on internal devices.
- Reboot afterwards. Dual busmode is supported, but works only for the
- internal bus, yet. External bus is still ignored. Take care for your
- SCSI-ids. If combined bus-mode is activated, on some adapters,
- the wide-addressing is not possible, so devices with ids between 8
- and 15 get ignored by the driver & adapter!
- Q: I have a 9595 and I get a NMI during heavy SCSI I/O e.g. during fsck.
- A COMMAND ERROR is reported and characters on the screen are missing.
- Warm reboot is not possible. Things look like quite weird.
- A: Check the processor type of your 9595. If you have an 80486 or 486DX-2
- processor complex on your mainboard and you compiled a kernel that
- supports 80386 processors, it is possible, that the kernel cannot
- keep track of the PS/2 interrupt handling and stops on an NMI. Just
- compile a kernel for the correct processor type of your PS/2 and
- everything should be fine. This is necessary even if one assumes,
- that some 80486 system should be downward compatible to 80386
- software.
- Q: Some commands hang and interrupts block the machine. After some
- timeout, the syslog reports that it tries to call abort, but the
- machine is frozen.
- A: This can be a busy wait bug in the interrupt handler of driver
- version 3.2. You should at least upgrade to 3.2c if you use
- kernel < 2.4.0 and driver version 4.0 if you use kernel 2.4.0 or
- later (including all test releases).
- Q: I have a PS/2 model 80 and more than 16 MBytes of RAM. The driver
- completely refuses to work, reports NMIs, COMMAND ERRORs or other
- ambiguous stuff. When reducing the RAM size down below 16 MB,
- everything is running smoothly.
- A: No real answer, yet. In any case, one should force the kernel to
- present SCBs only below the 16 MBytes barrier. Maybe this solves the
- problem. Not yet tried, but guessing that it could work. To get this,
- set unchecked_isa_dma argument of ibmmca.h from 0 to 1.
-
- 5.3 Bug reports
- --------------
- If you really find bugs in the source code or the driver will successfully
- refuse to work on your machine, you should send a bug report to me. The
- best for this is to follow the instructions on the WWW-page for this
- driver. Fill out the bug-report form, placed on the WWW-page and ship it,
- so the bugs can be taken into account with maximum efforts. But, please
- do not send bug reports about this driver to Linus Torvalds or Leonard
- Zubkoff, as Linus is buried in E-Mail and Leonard is supervising all
- SCSI-drivers and won't have the time left to look inside every single
- driver to fix a bug and especially DO NOT send modified code to Linus
- Torvalds or Alan J. Cox which has not been checked here!!! They are both
- quite buried in E-mail (as me, sometimes, too) and one should first check
- for problems on my local teststand. Recently, I got a lot of
- bug reports for errors in the ibmmca.c code, which I could not imagine, but
- a look inside some Linux-distribution showed me quite often some modified
- code, which did no longer work on most other machines than the one of the
- modifier. Ok, so now that there is maintenance service available for this
- driver, please use this address first in order to keep the level of
- confusion low. Thank you!
-
- When you get a SCSI-error message that panics your system, a list of
- register-entries of the SCSI-subsystem is shown (from Version 3.1d). With
- this list, it is very easy for the maintainer to localize the problem in
- the driver or in the configuration of the user. Please write down all the
- values from this report and send them to the maintainer. This would really
- help a lot and makes life easier concerning misunderstandings.
-
- Use the bug-report form (see 5.4 for its address) to send all the bug-
- stuff to the maintainer or write e-mail with the values from the table.
-
- 5.4 Support WWW-page
- --------------------
- The address of the IBM SCSI-subsystem supporting WWW-page is:
-
- http://www.staff.uni-mainz.de/mlang/linux.html
-
- Here you can find info about the background of this driver, patches,
- troubleshooting support, news and a bugreport form. Please check that
- WWW-page regularly for latest hints. If ever this URL changes, please
- refer to the MAINTAINERS file in order to get the latest address.
-
- For the bugreport, please fill out the formular on the corresponding
- WWW-page. Read the dedicated instructions and write as much as you
- know about your problem. If you do not like such formulars, please send
- some e-mail directly, but at least with the same information as required by
- the formular.
-
- If you have extensive bug reports, including Oops messages and
- screen-shots, please feel free to send it directly to the address
- of the maintainer, too. The current address of the maintainer is:
-
- Michael Lang <langa2@kph.uni-mainz.de>
-
- 6 References
- ------------
- IBM Corp., "Update for the PS/2 Hardware Interface Technical Reference,
- Common Interfaces", Armonk, September 1991, PN 04G3281,
- (available in the U.S. for $21.75 at 1-800-IBM-PCTB or in Germany for
- around 40,-DM at "Hallo IBM").
-
- IBM Corp., "Personal System/2 Micro Channel SCSI
- Adapter with Cache Technical Reference", Armonk, March 1990, PN 68X2365.
-
- IBM Corp., "Personal System/2 Micro Channel SCSI
- Adapter Technical Reference", Armonk, March 1990, PN 68X2397.
-
- IBM Corp., "SCSI-2 Fast/Wide Adapter/A Technical Reference - Dual Bus",
- Armonk, March 1994, PN 83G7545.
-
- Friedhelm Schmidt, "SCSI-Bus und IDE-Schnittstelle - Moderne Peripherie-
- Schnittstellen: Hardware, Protokollbeschreibung und Anwendung", 2. Aufl.
- Addison Wesley, 1996.
-
- Michael K. Johnson, "The Linux Kernel Hackers' Guide", Version 0.6, Chapel
- Hill - North Carolina, 1995
-
- Andreas Kaiser, "SCSI TAPE BACKUP for OS/2 2.0", Version 2.12, Stuttgart
- 1993
-
- Helmut Rompel, "IBM Computerwelt GUIDE", What is what bei IBM., Systeme *
- Programme * Begriffe, IWT-Verlag GmbH - Muenchen, 1988
-
- 7 Credits to
- ------------
- 7.1 People
- ----------
- Klaus Grimm
- who already a long time ago gave me the old code from the
- SCSI-driver in order to get it running for some old machine
- in our institute.
- Martin Kolinek
- who wrote the first release of the IBM SCSI-subsystem driver.
- Chris Beauregard
- who for a long time maintained MCA-Linux and the SCSI-driver
- in the beginning. Chris, wherever you are: Cheers to you!
- Klaus Kudielka
- with whom in the 2.1.x times, I had a quite fruitful
- cooperation to get the driver running as a module and to get
- it running with multiple SCSI-adapters.
- David Weinehall
- for his excellent maintenance of the MCA-stuff and the quite
- detailed bug reports and ideas for this driver (and his
- patience ;-)).
- Alan J. Cox
- for his bug reports and his bold activities in cross-checking
- the driver-code with his teststand.
-
- 7.2 Sponsors & Supporters
- -------------------------
- "Hallo IBM",
- IBM-Deutschland GmbH
- the service of IBM-Deutschland for customers. Their E-Mail
- service is unbeatable. Whatever old stuff I asked for, I
- always got some helpful answers.
- Karl-Otto Reimers,
- IBM Klub - Sparte IBM Geschichte, Sindelfingen
- for sending me a copy of the w/Cache manual from the
- IBM-Deutschland archives.
- Harald Staiger
- for his extensive hardware donations which allows me today
- still to test the driver in various constellations.
- Erich Fritscher
- for his very kind sponsoring.
- Louis Ohland,
- Charles Lasitter
- for support by shipping me an IBM SCSI-2 Fast/Wide manual.
- In addition, the contribution of various hardware is quite
- decessive and will make it possible to add FWSR (RAID)
- adapter support to the driver in the near future! So,
- complaints about no RAID support won't remain forever.
- Yes, folks, that is no joke, RAID support is going to rise!
- Erik Weber
- for the great deal we made about a model 9595 and the nice
- surrounding equipment and the cool trip to Mannheim
- second-hand computer market. In addition, I would like
- to thank him for his exhaustive SCSI-driver testing on his
- 95er PS/2 park.
- Anthony Hogbin
- for his direct shipment of a SCSI F/W adapter, which allowed
- me immediately on the first stage to try it on model 8557
- together with onboard SCSI adapter and some SCSI w/Cache.
- Andreas Hotz
- for his support by memory and an IBM SCSI-adapter. Collecting
- all this together now allows me to try really things with
- the driver at maximum load and variety on various models in
- a very quick and efficient way.
- Peter Jennewein
- for his model 30, which serves me as part of my teststand
- and his cool remark about how you make an ordinary diskette
- drive working and how to connect it to an IBM-diskette port.
- Johannes Gutenberg-Universitaet, Mainz &
- Institut fuer Kernphysik, Mainz Microtron (MAMI)
- for the offered space, the link, placed on the central
- homepage and the space to store and offer the driver and
- related material and the free working times, which allow
- me to answer all your e-mail.
-
- 8 Trademarks
- ------------
- IBM, PS/2, OS/2, Microchannel are registered trademarks of International
- Business Machines Corporation
-
- MS-DOS is a registered trademark of Microsoft Corporation
-
- Microware, OS-9 are registered trademarks of Microware Systems
-
- 9 Disclaimer
- ------------
- Beside the GNU General Public License and the dependent disclaimers and disclaimers
- concerning the Linux-kernel in special, this SCSI-driver comes without any
- warranty. Its functionality is tested as good as possible on certain
- machines and combinations of computer hardware, which does not exclude,
- that data loss or severe damage of hardware is possible while using this
- part of software on some arbitrary computer hardware or in combination
- with other software packages. It is highly recommended to make backup
- copies of your data before using this software. Furthermore, personal
- injuries by hardware defects, that could be caused by this SCSI-driver are
- not excluded and it is highly recommended to handle this driver with a
- maximum of carefulness.
-
- This driver supports hardware, produced by International Business Machines
- Corporation (IBM).
-
-------
-Michael Lang
-(langa2@kph.uni-mainz.de)