ACPI / Sleep: Allow the NVS saving to be skipped during suspend to RAM

Commit 2a6b69765ad794389f2fc3e14a0afa1a995221c2
(ACPI: Store NVS state even when entering suspend to RAM) caused the
ACPI suspend code save the NVS area during suspend and restore it
during resume unconditionally, although it is known that some systems
need to use acpi_sleep=s4_nonvs for hibernation to work.  To allow
the affected systems to avoid saving and restoring the NVS area
during suspend to RAM and resume, introduce kernel command line
option acpi_sleep=nonvs and make acpi_sleep=s4_nonvs work as its
alias temporarily (add acpi_sleep=s4_nonvs to the feature removal
file).

Addresses https://bugzilla.kernel.org/show_bug.cgi?id=16396 .

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Reported-and-tested-by: tomas m <tmezzadra@gmail.com>
Signed-off-by: Len Brown <len.brown@intel.com>

2 files changed, 9 insertions, 2 deletions

diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt
index c268783bc4e7..1571c0c83dba 100644
--- a/Documentation/feature-removal-schedule.txt
+++ b/Documentation/feature-removal-schedule.txt
@@ -647,3 +647,10 @@ Who:	Stefan Richter <stefanr@s5r6.in-berlin.de>
 
 ----------------------------
 
+What:   The acpi_sleep=s4_nonvs command line option
+When:   2.6.37
+Files:  arch/x86/kernel/acpi/sleep.c
+Why:    superseded by acpi_sleep=nonvs
+Who:    Rafael J. Wysocki <rjw@sisk.pl>
+
+----------------------------
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 4ddb58df081e..2b2407d9a6d0 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -254,8 +254,8 @@ and is between 256 and 4096 characters. It is defined in the file
                         control method, with respect to putting devices into
                         low power states, to be enforced (the ACPI 2.0 ordering
                         of _PTS is used by default).
-                        s4_nonvs prevents the kernel from saving/restoring the
-                        ACPI NVS memory during hibernation.
+                        nonvs prevents the kernel from saving/restoring the
+                        ACPI NVS memory during suspend/hibernation and resume.
                         sci_force_enable causes the kernel to set SCI_EN directly
                         on resume from S1/S3 (which is against the ACPI spec,
                         but some broken systems don't work without it).