This reverts commit cf450136bf.
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: Jörg 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: Linus Torvalds <torvalds@linux-foundation.org>
The reset register was only introduced with version 2 of the FADT, so we
should check that the FADT revision before trusting its contents.
Signed-off-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Windows ignores the bit_offset and bit_width, despite the spec requiring
that they be validated. Drop the checks so that we match this behaviour.
Windows also goes straight for the keyboard controller if the ACPI reboot
fails, so we shouldn't sleep if we're still alive.
Signed-off-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Changed the acpi_hw_low_level_read and acpi_hw_low_level_write functions to
the public acpi_read and acpi_write to allow direct access to
ACPI registers. Removed the "width" parameter since the width
can be obtained from the input GAS structure. Updated the FADT
initialization to setup the GAS structures with the proper
widths. Some widths are still hardcoded because many FADTs have
incorrect register lengths.
Signed-off-by: Bob Moore <robert.moore@intel.com
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
According to ACPI 3.0, FADT.flags.RESET_REG_SUP indicates
whether the ACPI reboot mechanism is supported.
However, some boxes have this bit clear, have a valid
ACPI_RESET_REG & RESET_VALUE, and ACPI reboot is the only
mechanism that works for them after S3.
This suggests that other operating systems may not be checking
the RESET_REG_SUP bit, and are using other means to decide
whether to use the ACPI reboot mechanism or not.
Here we stop checking RESET_REG_SUP.
Instead, When acpi reboot is requested,
only the reset_register is checked. If the following
conditions are met, it indicates that the reset register is supported.
a. reset_register is not zero
b. the access width is eight
c. the bit_offset is zero
http://bugzilla.kernel.org/show_bug.cgi?id=7299http://bugzilla.kernel.org/show_bug.cgi?id=1148
Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
