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-MORE NOTES ON HD-AUDIO DRIVER
-=============================
- Takashi Iwai <tiwai@suse.de>
-
-
-GENERAL
--------
-
-HD-audio is the new standard on-board audio component on modern PCs
-after AC97. Although Linux has been supporting HD-audio since long
-time ago, there are often problems with new machines. A part of the
-problem is broken BIOS, and the rest is the driver implementation.
-This document explains the brief trouble-shooting and debugging
-methods for the HD-audio hardware.
-
-The HD-audio component consists of two parts: the controller chip and
-the codec chips on the HD-audio bus. Linux provides a single driver
-for all controllers, snd-hda-intel. Although the driver name contains
-a word of a well-known hardware vendor, it's not specific to it but for
-all controller chips by other companies. Since the HD-audio
-controllers are supposed to be compatible, the single snd-hda-driver
-should work in most cases. But, not surprisingly, there are known
-bugs and issues specific to each controller type. The snd-hda-intel
-driver has a bunch of workarounds for these as described below.
-
-A controller may have multiple codecs. Usually you have one audio
-codec and optionally one modem codec. In theory, there might be
-multiple audio codecs, e.g. for analog and digital outputs, and the
-driver might not work properly because of conflict of mixer elements.
-This should be fixed in future if such hardware really exists.
-
-The snd-hda-intel driver has several different codec parsers depending
-on the codec. It has a generic parser as a fallback, but this
-functionality is fairly limited until now. Instead of the generic
-parser, usually the codec-specific parser (coded in patch_*.c) is used
-for the codec-specific implementations. The details about the
-codec-specific problems are explained in the later sections.
-
-If you are interested in the deep debugging of HD-audio, read the
-HD-audio specification at first. The specification is found on
-Intel's web page, for example:
-
-- http://www.intel.com/standards/hdaudio/
-
-
-HD-AUDIO CONTROLLER
--------------------
-
-DMA-Position Problem
-~~~~~~~~~~~~~~~~~~~~
-The most common problem of the controller is the inaccurate DMA
-pointer reporting. The DMA pointer for playback and capture can be
-read in two ways, either via a LPIB register or via a position-buffer
-map. As default the driver tries to read from the io-mapped
-position-buffer, and falls back to LPIB if the position-buffer appears
-dead. However, this detection isn't perfect on some devices. In such
-a case, you can change the default method via `position_fix` option.
-
-`position_fix=1` means to use LPIB method explicitly.
-`position_fix=2` means to use the position-buffer.
-`position_fix=3` means to use a combination of both methods, needed
-for some VIA controllers. The capture stream position is corrected
-by comparing both LPIB and position-buffer values.
-`position_fix=4` is another combination available for all controllers,
-and uses LPIB for the playback and the position-buffer for the capture
-streams.
-0 is the default value for all other
-controllers, the automatic check and fallback to LPIB as described in
-the above. If you get a problem of repeated sounds, this option might
-help.
-
-In addition to that, every controller is known to be broken regarding
-the wake-up timing. It wakes up a few samples before actually
-processing the data on the buffer. This caused a lot of problems, for
-example, with ALSA dmix or JACK. Since 2.6.27 kernel, the driver puts
-an artificial delay to the wake up timing. This delay is controlled
-via `bdl_pos_adj` option.
-
-When `bdl_pos_adj` is a negative value (as default), it's assigned to
-an appropriate value depending on the controller chip. For Intel
-chips, it'd be 1 while it'd be 32 for others. Usually this works.
-Only in case it doesn't work and you get warning messages, you should
-change this parameter to other values.
-
-
-Codec-Probing Problem
-~~~~~~~~~~~~~~~~~~~~~
-A less often but a more severe problem is the codec probing. When
-BIOS reports the available codec slots wrongly, the driver gets
-confused and tries to access the non-existing codec slot. This often
-results in the total screw-up, and destructs the further communication
-with the codec chips. The symptom appears usually as error messages
-like:
-------------------------------------------------------------------------
- hda_intel: azx_get_response timeout, switching to polling mode:
- last cmd=0x12345678
- hda_intel: azx_get_response timeout, switching to single_cmd mode:
- last cmd=0x12345678
-------------------------------------------------------------------------
-
-The first line is a warning, and this is usually relatively harmless.
-It means that the codec response isn't notified via an IRQ. The
-driver uses explicit polling method to read the response. It gives
-very slight CPU overhead, but you'd unlikely notice it.
-
-The second line is, however, a fatal error. If this happens, usually
-it means that something is really wrong. Most likely you are
-accessing a non-existing codec slot.
-
-Thus, if the second error message appears, try to narrow the probed
-codec slots via `probe_mask` option. It's a bitmask, and each bit
-corresponds to the codec slot. For example, to probe only the first
-slot, pass `probe_mask=1`. For the first and the third slots, pass
-`probe_mask=5` (where 5 = 1 | 4), and so on.
-
-Since 2.6.29 kernel, the driver has a more robust probing method, so
-this error might happen rarely, though.
-
-On a machine with a broken BIOS, sometimes you need to force the
-driver to probe the codec slots the hardware doesn't report for use.
-In such a case, turn the bit 8 (0x100) of `probe_mask` option on.
-Then the rest 8 bits are passed as the codec slots to probe
-unconditionally. For example, `probe_mask=0x103` will force to probe
-the codec slots 0 and 1 no matter what the hardware reports.
-
-
-Interrupt Handling
-~~~~~~~~~~~~~~~~~~
-HD-audio driver uses MSI as default (if available) since 2.6.33
-kernel as MSI works better on some machines, and in general, it's
-better for performance. However, Nvidia controllers showed bad
-regressions with MSI (especially in a combination with AMD chipset),
-thus we disabled MSI for them.
-
-There seem also still other devices that don't work with MSI. If you
-see a regression wrt the sound quality (stuttering, etc) or a lock-up
-in the recent kernel, try to pass `enable_msi=0` option to disable
-MSI. If it works, you can add the known bad device to the blacklist
-defined in hda_intel.c. In such a case, please report and give the
-patch back to the upstream developer.
-
-
-HD-AUDIO CODEC
---------------
-
-Model Option
-~~~~~~~~~~~~
-The most common problem regarding the HD-audio driver is the
-unsupported codec features or the mismatched device configuration.
-Most of codec-specific code has several preset models, either to
-override the BIOS setup or to provide more comprehensive features.
-
-The driver checks PCI SSID and looks through the static configuration
-table until any matching entry is found. If you have a new machine,
-you may see a message like below:
-------------------------------------------------------------------------
- hda_codec: ALC880: BIOS auto-probing.
-------------------------------------------------------------------------
-Meanwhile, in the earlier versions, you would see a message like:
-------------------------------------------------------------------------
- hda_codec: Unknown model for ALC880, trying auto-probe from BIOS...
-------------------------------------------------------------------------
-Even if you see such a message, DON'T PANIC. Take a deep breath and
-keep your towel. First of all, it's an informational message, no
-warning, no error. This means that the PCI SSID of your device isn't
-listed in the known preset model (white-)list. But, this doesn't mean
-that the driver is broken. Many codec-drivers provide the automatic
-configuration mechanism based on the BIOS setup.
-
-The HD-audio codec has usually "pin" widgets, and BIOS sets the default
-configuration of each pin, which indicates the location, the
-connection type, the jack color, etc. The HD-audio driver can guess
-the right connection judging from these default configuration values.
-However -- some codec-support codes, such as patch_analog.c, don't
-support the automatic probing (yet as of 2.6.28). And, BIOS is often,
-yes, pretty often broken. It sets up wrong values and screws up the
-driver.
-
-The preset model is provided basically to overcome such a situation.
-When the matching preset model is found in the white-list, the driver
-assumes the static configuration of that preset and builds the mixer
-elements and PCM streams based on the static information. Thus, if
-you have a newer machine with a slightly different PCI SSID from the
-existing one, you may have a good chance to re-use the same model.
-You can pass the `model` option to specify the preset model instead of
-PCI SSID look-up.
-
-What `model` option values are available depends on the codec chip.
-Check your codec chip from the codec proc file (see "Codec Proc-File"
-section below). It will show the vendor/product name of your codec
-chip. Then, see Documentation/sound/alsa/HD-Audio-Models.txt file,
-the section of HD-audio driver. You can find a list of codecs
-and `model` options belonging to each codec. For example, for Realtek
-ALC262 codec chip, pass `model=ultra` for devices that are compatible
-with Samsung Q1 Ultra.
-
-Thus, the first thing you can do for any brand-new, unsupported and
-non-working HD-audio hardware is to check HD-audio codec and several
-different `model` option values. If you have any luck, some of them
-might suit with your device well.
-
-Some codecs such as ALC880 have a special model option `model=test`.
-This configures the driver to provide as many mixer controls as
-possible for every single pin feature except for the unsolicited
-events (and maybe some other specials). Adjust each mixer element and
-try the I/O in the way of trial-and-error until figuring out the whole
-I/O pin mappings.
-
-Note that `model=generic` has a special meaning. It means to use the
-generic parser regardless of the codec. Usually the codec-specific
-parser is much better than the generic parser (as now). Thus this
-option is more about the debugging purpose.
-
-Speaker and Headphone Output
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-One of the most frequent (and obvious) bugs with HD-audio is the
-silent output from either or both of a built-in speaker and a
-headphone jack. In general, you should try a headphone output at
-first. A speaker output often requires more additional controls like
-the external amplifier bits. Thus a headphone output has a slightly
-better chance.
-
-Before making a bug report, double-check whether the mixer is set up
-correctly. The recent version of snd-hda-intel driver provides mostly
-"Master" volume control as well as "Front" volume (where Front
-indicates the front-channels). In addition, there can be individual
-"Headphone" and "Speaker" controls.
-
-Ditto for the speaker output. There can be "External Amplifier"
-switch on some codecs. Turn on this if present.
-
-Another related problem is the automatic mute of speaker output by
-headphone plugging. This feature is implemented in most cases, but
-not on every preset model or codec-support code.
-
-In anyway, try a different model option if you have such a problem.
-Some other models may match better and give you more matching
-functionality. If none of the available models works, send a bug
-report. See the bug report section for details.
-
-If you are masochistic enough to debug the driver problem, note the
-following:
-
-- The speaker (and the headphone, too) output often requires the
- external amplifier. This can be set usually via EAPD verb or a
- certain GPIO. If the codec pin supports EAPD, you have a better
- chance via SET_EAPD_BTL verb (0x70c). On others, GPIO pin (mostly
- it's either GPIO0 or GPIO1) may turn on/off EAPD.
-- Some Realtek codecs require special vendor-specific coefficients to
- turn on the amplifier. See patch_realtek.c.
-- IDT codecs may have extra power-enable/disable controls on each
- analog pin. See patch_sigmatel.c.
-- Very rare but some devices don't accept the pin-detection verb until
- triggered. Issuing GET_PIN_SENSE verb (0xf09) may result in the
- codec-communication stall. Some examples are found in
- patch_realtek.c.
-
-
-Capture Problems
-~~~~~~~~~~~~~~~~
-The capture problems are often because of missing setups of mixers.
-Thus, before submitting a bug report, make sure that you set up the
-mixer correctly. For example, both "Capture Volume" and "Capture
-Switch" have to be set properly in addition to the right "Capture
-Source" or "Input Source" selection. Some devices have "Mic Boost"
-volume or switch.
-
-When the PCM device is opened via "default" PCM (without pulse-audio
-plugin), you'll likely have "Digital Capture Volume" control as well.
-This is provided for the extra gain/attenuation of the signal in
-software, especially for the inputs without the hardware volume
-control such as digital microphones. Unless really needed, this
-should be set to exactly 50%, corresponding to 0dB -- neither extra
-gain nor attenuation. When you use "hw" PCM, i.e., a raw access PCM,
-this control will have no influence, though.
-
-It's known that some codecs / devices have fairly bad analog circuits,
-and the recorded sound contains a certain DC-offset. This is no bug
-of the driver.
-
-Most of modern laptops have no analog CD-input connection. Thus, the
-recording from CD input won't work in many cases although the driver
-provides it as the capture source. Use CDDA instead.
-
-The automatic switching of the built-in and external mic per plugging
-is implemented on some codec models but not on every model. Partly
-because of my laziness but mostly lack of testers. Feel free to
-submit the improvement patch to the author.
-
-
-Direct Debugging
-~~~~~~~~~~~~~~~~
-If no model option gives you a better result, and you are a tough guy
-to fight against evil, try debugging via hitting the raw HD-audio
-codec verbs to the device. Some tools are available: hda-emu and
-hda-analyzer. The detailed description is found in the sections
-below. You'd need to enable hwdep for using these tools. See "Kernel
-Configuration" section.
-
-
-OTHER ISSUES
-------------
-
-Kernel Configuration
-~~~~~~~~~~~~~~~~~~~~
-In general, I recommend you to enable the sound debug option,
-`CONFIG_SND_DEBUG=y`, no matter whether you are debugging or not.
-This enables snd_printd() macro and others, and you'll get additional
-kernel messages at probing.
-
-In addition, you can enable `CONFIG_SND_DEBUG_VERBOSE=y`. But this
-will give you far more messages. Thus turn this on only when you are
-sure to want it.
-
-Don't forget to turn on the appropriate `CONFIG_SND_HDA_CODEC_*`
-options. Note that each of them corresponds to the codec chip, not
-the controller chip. Thus, even if lspci shows the Nvidia controller,
-you may need to choose the option for other vendors. If you are
-unsure, just select all yes.
-
-`CONFIG_SND_HDA_HWDEP` is a useful option for debugging the driver.
-When this is enabled, the driver creates hardware-dependent devices
-(one per each codec), and you have a raw access to the device via
-these device files. For example, `hwC0D2` will be created for the
-codec slot #2 of the first card (#0). For debug-tools such as
-hda-verb and hda-analyzer, the hwdep device has to be enabled.
-Thus, it'd be better to turn this on always.
-
-`CONFIG_SND_HDA_RECONFIG` is a new option, and this depends on the
-hwdep option above. When enabled, you'll have some sysfs files under
-the corresponding hwdep directory. See "HD-audio reconfiguration"
-section below.
-
-`CONFIG_SND_HDA_POWER_SAVE` option enables the power-saving feature.
-See "Power-saving" section below.
-
-
-Codec Proc-File
-~~~~~~~~~~~~~~~
-The codec proc-file is a treasure-chest for debugging HD-audio.
-It shows most of useful information of each codec widget.
-
-The proc file is located in /proc/asound/card*/codec#*, one file per
-each codec slot. You can know the codec vendor, product id and
-names, the type of each widget, capabilities and so on.
-This file, however, doesn't show the jack sensing state, so far. This
-is because the jack-sensing might be depending on the trigger state.
-
-This file will be picked up by the debug tools, and also it can be fed
-to the emulator as the primary codec information. See the debug tools
-section below.
-
-This proc file can be also used to check whether the generic parser is
-used. When the generic parser is used, the vendor/product ID name
-will appear as "Realtek ID 0262", instead of "Realtek ALC262".
-
-
-HD-Audio Reconfiguration
-~~~~~~~~~~~~~~~~~~~~~~~~
-This is an experimental feature to allow you re-configure the HD-audio
-codec dynamically without reloading the driver. The following sysfs
-files are available under each codec-hwdep device directory (e.g.
-/sys/class/sound/hwC0D0):
-
-vendor_id::
- Shows the 32bit codec vendor-id hex number. You can change the
- vendor-id value by writing to this file.
-subsystem_id::
- Shows the 32bit codec subsystem-id hex number. You can change the
- subsystem-id value by writing to this file.
-revision_id::
- Shows the 32bit codec revision-id hex number. You can change the
- revision-id value by writing to this file.
-afg::
- Shows the AFG ID. This is read-only.
-mfg::
- Shows the MFG ID. This is read-only.
-name::
- Shows the codec name string. Can be changed by writing to this
- file.
-modelname::
- Shows the currently set `model` option. Can be changed by writing
- to this file.
-init_verbs::
- The extra verbs to execute at initialization. You can add a verb by
- writing to this file. Pass three numbers: nid, verb and parameter
- (separated with a space).
-hints::
- Shows / stores hint strings for codec parsers for any use.
- Its format is `key = value`. For example, passing `hp_detect = yes`
- to IDT/STAC codec parser will result in the disablement of the
- headphone detection.
-init_pin_configs::
- Shows the initial pin default config values set by BIOS.
-driver_pin_configs::
- Shows the pin default values set by the codec parser explicitly.
- This doesn't show all pin values but only the changed values by
- the parser. That is, if the parser doesn't change the pin default
- config values by itself, this will contain nothing.
-user_pin_configs::
- Shows the pin default config values to override the BIOS setup.
- Writing this (with two numbers, NID and value) appends the new
- value. The given will be used instead of the initial BIOS value at
- the next reconfiguration time. Note that this config will override
- even the driver pin configs, too.
-reconfig::
- Triggers the codec re-configuration. When any value is written to
- this file, the driver re-initialize and parses the codec tree
- again. All the changes done by the sysfs entries above are taken
- into account.
-clear::
- Resets the codec, removes the mixer elements and PCM stuff of the
- specified codec, and clear all init verbs and hints.
-
-For example, when you want to change the pin default configuration
-value of the pin widget 0x14 to 0x9993013f, and let the driver
-re-configure based on that state, run like below:
-------------------------------------------------------------------------
- # echo 0x14 0x9993013f > /sys/class/sound/hwC0D0/user_pin_configs
- # echo 1 > /sys/class/sound/hwC0D0/reconfig
-------------------------------------------------------------------------
-
-
-Early Patching
-~~~~~~~~~~~~~~
-When CONFIG_SND_HDA_PATCH_LOADER=y is set, you can pass a "patch" as a
-firmware file for modifying the HD-audio setup before initializing the
-codec. This can work basically like the reconfiguration via sysfs in
-the above, but it does it before the first codec configuration.
-
-A patch file is a plain text file which looks like below:
-
-------------------------------------------------------------------------
- [codec]
- 0x12345678 0xabcd1234 2
-
- [model]
- auto
-
- [pincfg]
- 0x12 0x411111f0
-
- [verb]
- 0x20 0x500 0x03
- 0x20 0x400 0xff
-
- [hint]
- hp_detect = yes
-------------------------------------------------------------------------
-
-The file needs to have a line `[codec]`. The next line should contain
-three numbers indicating the codec vendor-id (0x12345678 in the
-example), the codec subsystem-id (0xabcd1234) and the address (2) of
-the codec. The rest patch entries are applied to this specified codec
-until another codec entry is given. Passing 0 or a negative number to
-the first or the second value will make the check of the corresponding
-field be skipped. It'll be useful for really broken devices that don't
-initialize SSID properly.
-
-The `[model]` line allows to change the model name of the each codec.
-In the example above, it will be changed to model=auto.
-Note that this overrides the module option.
-
-After the `[pincfg]` line, the contents are parsed as the initial
-default pin-configurations just like `user_pin_configs` sysfs above.
-The values can be shown in user_pin_configs sysfs file, too.
-
-Similarly, the lines after `[verb]` are parsed as `init_verbs`
-sysfs entries, and the lines after `[hint]` are parsed as `hints`
-sysfs entries, respectively.
-
-Another example to override the codec vendor id from 0x12345678 to
-0xdeadbeef is like below:
-------------------------------------------------------------------------
- [codec]
- 0x12345678 0xabcd1234 2
-
- [vendor_id]
- 0xdeadbeef
-------------------------------------------------------------------------
-
-In the similar way, you can override the codec subsystem_id via
-`[subsystem_id]`, the revision id via `[revision_id]` line.
-Also, the codec chip name can be rewritten via `[chip_name]` line.
-------------------------------------------------------------------------
- [codec]
- 0x12345678 0xabcd1234 2
-
- [subsystem_id]
- 0xffff1111
-
- [revision_id]
- 0x10
-
- [chip_name]
- My-own NEWS-0002
-------------------------------------------------------------------------
-
-The hd-audio driver reads the file via request_firmware(). Thus,
-a patch file has to be located on the appropriate firmware path,
-typically, /lib/firmware. For example, when you pass the option
-`patch=hda-init.fw`, the file /lib/firmware/hda-init.fw must be
-present.
-
-The patch module option is specific to each card instance, and you
-need to give one file name for each instance, separated by commas.
-For example, if you have two cards, one for an on-board analog and one
-for an HDMI video board, you may pass patch option like below:
-------------------------------------------------------------------------
- options snd-hda-intel patch=on-board-patch,hdmi-patch
-------------------------------------------------------------------------
-
-
-Power-Saving
-~~~~~~~~~~~~
-The power-saving is a kind of auto-suspend of the device. When the
-device is inactive for a certain time, the device is automatically
-turned off to save the power. The time to go down is specified via
-`power_save` module option, and this option can be changed dynamically
-via sysfs.
-
-The power-saving won't work when the analog loopback is enabled on
-some codecs. Make sure that you mute all unneeded signal routes when
-you want the power-saving.
-
-The power-saving feature might cause audible click noises at each
-power-down/up depending on the device. Some of them might be
-solvable, but some are hard, I'm afraid. Some distros such as
-openSUSE enables the power-saving feature automatically when the power
-cable is unplugged. Thus, if you hear noises, suspect first the
-power-saving. See /sys/module/snd_hda_intel/parameters/power_save to
-check the current value. If it's non-zero, the feature is turned on.
-
-
-Tracepoints
-~~~~~~~~~~~
-The hd-audio driver gives a few basic tracepoints.
-`hda:hda_send_cmd` traces each CORB write while `hda:hda_get_response`
-traces the response from RIRB (only when read from the codec driver).
-`hda:hda_bus_reset` traces the bus-reset due to fatal error, etc,
-`hda:hda_unsol_event` traces the unsolicited events, and
-`hda:hda_power_down` and `hda:hda_power_up` trace the power down/up
-via power-saving behavior.
-
-Enabling all tracepoints can be done like
-------------------------------------------------------------------------
- # echo 1 > /sys/kernel/debug/tracing/events/hda/enable
-------------------------------------------------------------------------
-then after some commands, you can traces from
-/sys/kernel/debug/tracing/trace file. For example, when you want to
-trace what codec command is sent, enable the tracepoint like:
-------------------------------------------------------------------------
- # cat /sys/kernel/debug/tracing/trace
- # tracer: nop
- #
- # TASK-PID CPU# TIMESTAMP FUNCTION
- # | | | | |
- <...>-7807 [002] 105147.774889: hda_send_cmd: [0:0] val=e3a019
- <...>-7807 [002] 105147.774893: hda_send_cmd: [0:0] val=e39019
- <...>-7807 [002] 105147.999542: hda_send_cmd: [0:0] val=e3a01a
- <...>-7807 [002] 105147.999543: hda_send_cmd: [0:0] val=e3901a
- <...>-26764 [001] 349222.837143: hda_send_cmd: [0:0] val=e3a019
- <...>-26764 [001] 349222.837148: hda_send_cmd: [0:0] val=e39019
- <...>-26764 [001] 349223.058539: hda_send_cmd: [0:0] val=e3a01a
- <...>-26764 [001] 349223.058541: hda_send_cmd: [0:0] val=e3901a
-------------------------------------------------------------------------
-Here `[0:0]` indicates the card number and the codec address, and
-`val` shows the value sent to the codec, respectively. The value is
-a packed value, and you can decode it via hda-decode-verb program
-included in hda-emu package below. For example, the value e3a019 is
-to set the left output-amp value to 25.
-------------------------------------------------------------------------
- % hda-decode-verb 0xe3a019
- raw value = 0x00e3a019
- cid = 0, nid = 0x0e, verb = 0x3a0, parm = 0x19
- raw value: verb = 0x3a0, parm = 0x19
- verbname = set_amp_gain_mute
- amp raw val = 0xa019
- output, left, idx=0, mute=0, val=25
-------------------------------------------------------------------------
-
-
-Development Tree
-~~~~~~~~~~~~~~~~
-The latest development codes for HD-audio are found on sound git tree:
-
-- git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound.git
-
-The master branch or for-next branches can be used as the main
-development branches in general while the HD-audio specific patches
-are committed in topic/hda branch.
-
-If you are using the latest Linus tree, it'd be better to pull the
-above GIT tree onto it. If you are using the older kernels, an easy
-way to try the latest ALSA code is to build from the snapshot
-tarball. There are daily tarballs and the latest snapshot tarball.
-All can be built just like normal alsa-driver release packages, that
-is, installed via the usual spells: configure, make and make
-install(-modules). See INSTALL in the package. The snapshot tarballs
-are found at:
-
-- ftp://ftp.suse.com/pub/people/tiwai/snapshot/
-
-
-Sending a Bug Report
-~~~~~~~~~~~~~~~~~~~~
-If any model or module options don't work for your device, it's time
-to send a bug report to the developers. Give the following in your
-bug report:
-
-- Hardware vendor, product and model names
-- Kernel version (and ALSA-driver version if you built externally)
-- `alsa-info.sh` output; run with `--no-upload` option. See the
- section below about alsa-info
-
-If it's a regression, at best, send alsa-info outputs of both working
-and non-working kernels. This is really helpful because we can
-compare the codec registers directly.
-
-Send a bug report either the followings:
-
-kernel-bugzilla::
- https://bugzilla.kernel.org/
-alsa-devel ML::
- alsa-devel@alsa-project.org
-
-
-DEBUG TOOLS
------------
-
-This section describes some tools available for debugging HD-audio
-problems.
-
-alsa-info
-~~~~~~~~~
-The script `alsa-info.sh` is a very useful tool to gather the audio
-device information. You can fetch the latest version from:
-
-- http://www.alsa-project.org/alsa-info.sh
-
-Run this script as root, and it will gather the important information
-such as the module lists, module parameters, proc file contents
-including the codec proc files, mixer outputs and the control
-elements. As default, it will store the information onto a web server
-on alsa-project.org. But, if you send a bug report, it'd be better to
-run with `--no-upload` option, and attach the generated file.
-
-There are some other useful options. See `--help` option output for
-details.
-
-When a probe error occurs or when the driver obviously assigns a
-mismatched model, it'd be helpful to load the driver with
-`probe_only=1` option (at best after the cold reboot) and run
-alsa-info at this state. With this option, the driver won't configure
-the mixer and PCM but just tries to probe the codec slot. After
-probing, the proc file is available, so you can get the raw codec
-information before modified by the driver. Of course, the driver
-isn't usable with `probe_only=1`. But you can continue the
-configuration via hwdep sysfs file if hda-reconfig option is enabled.
-Using `probe_only` mask 2 skips the reset of HDA codecs (use
-`probe_only=3` as module option). The hwdep interface can be used
-to determine the BIOS codec initialization.
-
-
-hda-verb
-~~~~~~~~
-hda-verb is a tiny program that allows you to access the HD-audio
-codec directly. You can execute a raw HD-audio codec verb with this.
-This program accesses the hwdep device, thus you need to enable the
-kernel config `CONFIG_SND_HDA_HWDEP=y` beforehand.
-
-The hda-verb program takes four arguments: the hwdep device file, the
-widget NID, the verb and the parameter. When you access to the codec
-on the slot 2 of the card 0, pass /dev/snd/hwC0D2 to the first
-argument, typically. (However, the real path name depends on the
-system.)
-
-The second parameter is the widget number-id to access. The third
-parameter can be either a hex/digit number or a string corresponding
-to a verb. Similarly, the last parameter is the value to write, or
-can be a string for the parameter type.
-
-------------------------------------------------------------------------
- % hda-verb /dev/snd/hwC0D0 0x12 0x701 2
- nid = 0x12, verb = 0x701, param = 0x2
- value = 0x0
-
- % hda-verb /dev/snd/hwC0D0 0x0 PARAMETERS VENDOR_ID
- nid = 0x0, verb = 0xf00, param = 0x0
- value = 0x10ec0262
-
- % hda-verb /dev/snd/hwC0D0 2 set_a 0xb080
- nid = 0x2, verb = 0x300, param = 0xb080
- value = 0x0
-------------------------------------------------------------------------
-
-Although you can issue any verbs with this program, the driver state
-won't be always updated. For example, the volume values are usually
-cached in the driver, and thus changing the widget amp value directly
-via hda-verb won't change the mixer value.
-
-The hda-verb program is found in the ftp directory:
-
-- ftp://ftp.suse.com/pub/people/tiwai/misc/
-
-Also a git repository is available:
-
-- git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/hda-verb.git
-
-See README file in the tarball for more details about hda-verb
-program.
-
-
-hda-analyzer
-~~~~~~~~~~~~
-hda-analyzer provides a graphical interface to access the raw HD-audio
-control, based on pyGTK2 binding. It's a more powerful version of
-hda-verb. The program gives you an easy-to-use GUI stuff for showing
-the widget information and adjusting the amp values, as well as the
-proc-compatible output.
-
-The hda-analyzer:
-
-- http://git.alsa-project.org/?p=alsa.git;a=tree;f=hda-analyzer
-
-is a part of alsa.git repository in alsa-project.org:
-
-- git://git.alsa-project.org/alsa.git
-
-Codecgraph
-~~~~~~~~~~
-Codecgraph is a utility program to generate a graph and visualizes the
-codec-node connection of a codec chip. It's especially useful when
-you analyze or debug a codec without a proper datasheet. The program
-parses the given codec proc file and converts to SVG via graphiz
-program.
-
-The tarball and GIT trees are found in the web page at:
-
-- http://helllabs.org/codecgraph/
-
-
-hda-emu
-~~~~~~~
-hda-emu is an HD-audio emulator. The main purpose of this program is
-to debug an HD-audio codec without the real hardware. Thus, it
-doesn't emulate the behavior with the real audio I/O, but it just
-dumps the codec register changes and the ALSA-driver internal changes
-at probing and operating the HD-audio driver.
-
-The program requires a codec proc-file to simulate. Get a proc file
-for the target codec beforehand, or pick up an example codec from the
-codec proc collections in the tarball. Then, run the program with the
-proc file, and the hda-emu program will start parsing the codec file
-and simulates the HD-audio driver:
-
-------------------------------------------------------------------------
- % hda-emu codecs/stac9200-dell-d820-laptop
- # Parsing..
- hda_codec: Unknown model for STAC9200, using BIOS defaults
- hda_codec: pin nid 08 bios pin config 40c003fa
- ....
-------------------------------------------------------------------------
-
-The program gives you only a very dumb command-line interface. You
-can get a proc-file dump at the current state, get a list of control
-(mixer) elements, set/get the control element value, simulate the PCM
-operation, the jack plugging simulation, etc.
-
-The package is found in:
-
-- ftp://ftp.suse.com/pub/people/tiwai/misc/
-
-A git repository is available:
-
-- git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/hda-emu.git
-
-See README file in the tarball for more details about hda-emu
-program.