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authorShaohua Li <shaohua.li@intel.com>2008-07-23 21:28:41 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-07-24 10:47:24 -0700
commitbdfe6b7c681669148dae4db27eb24ee5408ba371 (patch)
tree644b84a7e4a329a635d9a9bc02102424cfb616e2 /Documentation
parent2f15fc4bdf91eb399da3f47a09c55831d9f22826 (diff)
pm: acpi hibernation: utilize hardware signature
ACPI defines a hardware signature. BIOS calculates the signature according to hardware configure and if hardware changes while hibernated, the signature will change. In that case, S4 resume should fail. Still, there may be systems on which this mechanism does not work correctly, so it is better to provide a workaround for them. For this reason, add a new switch to the acpi_sleep= command line argument allowing one to disable hardware signature checking. [shaohua.li@intel.com: build fix] Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Cc: Andi Kleen <andi@firstfloor.org> Cc: Len Brown <lenb@kernel.org> Acked-by: Pavel Machek <pavel@ucw.cz> Cc: <Valdis.Kletnieks@vt.edu> Cc: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/kernel-parameters.txt4
1 files changed, 3 insertions, 1 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 4d705713cab..497a98dafda 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -148,10 +148,12 @@ and is between 256 and 4096 characters. It is defined in the file
default: 0
acpi_sleep= [HW,ACPI] Sleep options
- Format: { s3_bios, s3_mode, s3_beep, old_ordering }
+ Format: { s3_bios, s3_mode, s3_beep, s4_nohwsig, old_ordering }
See Documentation/power/video.txt for s3_bios and s3_mode.
s3_beep is for debugging; it makes the PC's speaker beep
as soon as the kernel's real-mode entry point is called.
+ s4_nohwsig prevents ACPI hardware signature from being
+ used during resume from hibernation.
old_ordering causes the ACPI 1.0 ordering of the _PTS
control method, wrt putting devices into low power
states, to be enforced (the ACPI 2.0 ordering of _PTS is