ACPI / Sleep: add acpi_sleep=nonvs_s3 parameter

The ACPI specificiation would like us to save NVS at hibernation time,
but makes no mention of saving NVS over S3.  Not all versions of
Windows do this either, and it is clear that not all machines need NVS
saved/restored over S3.  Allow the user to improve their suspend/resume
time by disabling the NVS save/restore at S3 time, but continue to do
the NVS save/restore for S4 as specified.

Signed-off-by: Kristen Carlson Accardi <kristen@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/arch/x86/kernel/acpi/sleep.c b/arch/x86/kernel/acpi/sleep.c
index 11676cf65aee5ee51b64c8fadda0261c1f38599f..d5e0d717005abd1f9b610ff1ce39beaefaa080f0 100644 (file)
--- a/arch/x86/kernel/acpi/sleep.c
+++ b/arch/x86/kernel/acpi/sleep.c
@@ -101,6 +101,8 @@ static int __init acpi_sleep_setup(char *str)
 #endif
                if (strncmp(str, "nonvs", 5) == 0)
                        acpi_nvs_nosave();
+               if (strncmp(str, "nonvs_s3", 8) == 0)
+                       acpi_nvs_nosave_s3();
                if (strncmp(str, "old_ordering", 12) == 0)
                        acpi_old_suspend_ordering();
                str = strchr(str, ',');

diff --git a/drivers/acpi/sleep.c b/drivers/acpi/sleep.c
index fdcdbb652915a32340d91a7d6e6fcce15c3ee602..8640782944cc58e02da1e2e50d27e258777aa161 100644 (file)
--- a/drivers/acpi/sleep.c
+++ b/drivers/acpi/sleep.c
@@ -97,6 +97,21 @@ void __init acpi_nvs_nosave(void)
        nvs_nosave = true;
 }
 
+/*
+ * The ACPI specification wants us to save NVS memory regions during hibernation
+ * but says nothing about saving NVS during S3.  Not all versions of Windows
+ * save NVS on S3 suspend either, and it is clear that not all systems need
+ * NVS to be saved at S3 time.  To improve suspend/resume time, allow the
+ * user to disable saving NVS on S3 if their system does not require it, but
+ * continue to save/restore NVS for S4 as specified.
+ */
+static bool nvs_nosave_s3;
+
+void __init acpi_nvs_nosave_s3(void)
+{
+       nvs_nosave_s3 = true;
+}
+
 /*
  * ACPI 1.0 wants us to execute _PTS before suspending devices, so we allow the
  * user to request that behavior by using the 'acpi_old_suspend_ordering'
@@ -243,7 +258,7 @@ static int acpi_suspend_begin(suspend_state_t pm_state)
        u32 acpi_state = acpi_suspend_states[pm_state];
        int error = 0;
 
-       error = nvs_nosave ? 0 : suspend_nvs_alloc();
+       error = (nvs_nosave || nvs_nosave_s3) ? 0 : suspend_nvs_alloc();
        if (error)
                return error;
 

diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 90be9898110202f918a3d75d72da9437bb249bc5..3cf93491125c08dfc19d457aa07a9e6d7bd97338 100644 (file)
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -261,6 +261,7 @@ int acpi_resources_are_enforced(void);
 void __init acpi_no_s4_hw_signature(void);
 void __init acpi_old_suspend_ordering(void);
 void __init acpi_nvs_nosave(void);
+void __init acpi_nvs_nosave_s3(void);
 #endif /* CONFIG_PM_SLEEP */
 
 struct acpi_osc_context {