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Improve our reboot handling for compatibility with Windows. Upstream in .38?
diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c
index c495aa8..c770e66 100644
--- a/arch/x86/kernel/reboot.c
+++ b/arch/x86/kernel/reboot.c
@@ -34,7 +34,7 @@ EXPORT_SYMBOL(pm_power_off);
static const struct desc_ptr no_idt = {};
static int reboot_mode;
-enum reboot_type reboot_type = BOOT_KBD;
+enum reboot_type reboot_type = BOOT_ACPI;
int reboot_force;
#if defined(CONFIG_X86_32) && defined(CONFIG_SMP)
@@ -538,9 +538,23 @@ void __attribute__((weak)) mach_reboot_fixups(void)
{
}
+/*
+ * Windows does the following on reboot:
+ * 1) If the FADT has the ACPI reboot register flag set, try it
+ * 2) If still alive, write to the keyboard controller
+ * 3) If still alive, write to the ACPI reboot register again
+ * 4) Ig still alive, write to the keyboard controller again
+ *
+ * If the machine is still alive at this stage, it gives up. We default to
+ * following the same pattern, except that if we're still alive after (4) we'll
+ * try to force a triple fault and then cycle between hitting the keyboard
+ * controller and doing that
+ */
static void native_machine_emergency_restart(void)
{
int i;
+ int attempt = 0;
+ int orig_reboot_type = reboot_type;
if (reboot_emergency)
emergency_vmx_disable_all();
@@ -562,6 +576,13 @@ static void native_machine_emergency_restart(void)
outb(0xfe, 0x64); /* pulse reset low */
udelay(50);
}
+ if (attempt == 0 && orig_reboot_type == BOOT_ACPI) {
+ attempt = 1;
+ reboot_type = BOOT_ACPI;
+ } else {
+ reboot_type = BOOT_TRIPLE;
+ }
+ break;
case BOOT_TRIPLE:
load_idt(&no_idt);
diff --git a/drivers/acpi/acpica/hwxface.c b/drivers/acpi/acpica/hwxface.c
index 50cc3be..c6a4e63 100644
--- a/drivers/acpi/acpica/hwxface.c
+++ b/drivers/acpi/acpica/hwxface.c
@@ -82,12 +82,11 @@ acpi_status acpi_reset(void)
/*
* For I/O space, write directly to the OSL. This bypasses the port
* validation mechanism, which may block a valid write to the reset
- * register.
+ * register. Spec section 4.7.3.6 requires register width to be 8.
*/
status =
acpi_os_write_port((acpi_io_address) reset_reg->address,
- acpi_gbl_FADT.reset_value,
- reset_reg->bit_width);
+ acpi_gbl_FADT.reset_value, 8);
} else {
/* Write the reset value to the reset register */
diff --git a/drivers/acpi/reboot.c b/drivers/acpi/reboot.c
index 93f9114..a6c77e8b 100644
--- a/drivers/acpi/reboot.c
+++ b/drivers/acpi/reboot.c
@@ -15,9 +15,15 @@ void acpi_reboot(void)
rr = &acpi_gbl_FADT.reset_register;
- /* Is the reset register supported? */
- if (!(acpi_gbl_FADT.flags & ACPI_FADT_RESET_REGISTER) ||
- rr->bit_width != 8 || rr->bit_offset != 0)
+ /* ACPI reset register was only introduced with v2 of the FADT */
+
+ if (acpi_gbl_FADT.header.revision < 2)
+ return;
+
+ /* Is the reset register supported? The spec says we should be
+ * checking the bit width and bit offset, but Windows ignores
+ * these fields */
+ if (!(acpi_gbl_FADT.flags & ACPI_FADT_RESET_REGISTER))
return;
reset_value = acpi_gbl_FADT.reset_value;
@@ -45,6 +51,4 @@ void acpi_reboot(void)
acpi_reset();
break;
}
- /* Wait ten seconds */
- acpi_os_stall(10000000);
}
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