Commit 19244ad0 authored by Linus Torvalds's avatar Linus Torvalds

Revert "ACPI: ignore FADT reset-reg-sup flag"

This reverts commit cf450136.

It breaks reboot on at least one Thinkpad T43, as reported by Jörg Otte:
 "On reboot it shuts down as normal.
  The last lines displayed are:

  >Unmounting temporary filesystems.. [OK]
  >Deactivating swap...               [OK]
  >Unmounting local filesystems...    [OK]
  >Will now restart
  >    Restarting system

  Then I hear it accessing the cd-drive, but then it's being stuck."

Jörg bisected the regression to this commit.

That commit fixes another machine (see

  https://bugzilla.kernel.org/show_bug.cgi?id=11533

for details) that has a BIOS bug and doesn't support ACPI reset.
However, at least one of those other reporters no longer even has the
machine in question, and had a different workaround to begin with.
Besides, it clearly was a buggy BIOS.  Let's not break the correct case
to fix that case.
Reported-and-bisected-by: default avatarJörg Otte <jrg.otte@googlemail.com>
Cc: linux-acpi@vger.kernel.org
Cc: Len Brown <lenb@kernel.org>
Cc: Peter Anvin <hpa@zytor.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent b3dc627c
...@@ -74,7 +74,8 @@ acpi_status acpi_reset(void) ...@@ -74,7 +74,8 @@ acpi_status acpi_reset(void)
/* Check if the reset register is supported */ /* Check if the reset register is supported */
if (!reset_reg->address) { if (!(acpi_gbl_FADT.flags & ACPI_FADT_RESET_REGISTER) ||
!reset_reg->address) {
return_ACPI_STATUS(AE_NOT_EXIST); return_ACPI_STATUS(AE_NOT_EXIST);
} }
......
...@@ -23,7 +23,8 @@ void acpi_reboot(void) ...@@ -23,7 +23,8 @@ void acpi_reboot(void)
/* Is the reset register supported? The spec says we should be /* Is the reset register supported? The spec says we should be
* checking the bit width and bit offset, but Windows ignores * checking the bit width and bit offset, but Windows ignores
* these fields */ * these fields */
/* Ignore also acpi_gbl_FADT.flags.ACPI_FADT_RESET_REGISTER */ if (!(acpi_gbl_FADT.flags & ACPI_FADT_RESET_REGISTER))
return;
reset_value = acpi_gbl_FADT.reset_value; reset_value = acpi_gbl_FADT.reset_value;
......
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