[PATCH 2/2] ACPI: Store NVS state even when entering suspend to RAM

Matthew Garrett
2010-05-28T20:32:34Z

https://bugzilla.kernel.org/show_bug.cgi?id=13931 describes a bug where
a system fails to successfully resume after the second suspend. Maxim
Levitsky discovered that this could be rectified by forcibly saving
and restoring the ACPI non-volatile state. The spec indicates that this
is only required for S4, but testing the behaviour of Windows by adding
an ACPI NVS region to qemu's e820 map and registering a custom memory
read/write handler reveals that it's saved and restored even over suspend
to RAM. We should mimic that behaviour to avoid other broken platforms.

Signed-off-by: Matthew Garrett <mjg@redhat.com>
---
drivers/acpi/sleep.c | 21 +++++++++++++--------
1 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/drivers/acpi/sleep.c b/drivers/acpi/sleep.c
index d3cbc55..18aa074 100644
--- a/drivers/acpi/sleep.c
+++ b/drivers/acpi/sleep.c
@@ -128,6 +128,8 @@ static int __acpi_pm_prepare(void)
{
int error = acpi_sleep_prepare(acpi_target_sleep_state);

+ suspend_nvs_save();
+
if (error)
acpi_target_sleep_state = ACPI_STATE_S0;
return error;
@@ -156,6 +158,8 @@ static void acpi_pm_finish(void)
{
u32 acpi_state = acpi_target_sleep_state;

+ suspend_nvs_free();
+
if (acpi_state == ACPI_STATE_S0)
return;

@@ -205,6 +209,11 @@ static int acpi_suspend_begin(suspend_state_t pm_state)
u32 acpi_state = acpi_suspend_states[pm_state];
int error = 0;

+ error = suspend_nvs_alloc();
+
+ if (error)
+ return error;
+
if (sleep_states[acpi_state]) {
acpi_target_sleep_state = acpi_state;
acpi_sleep_tts_switch(acpi_target_sleep_state);
@@ -283,6 +292,8 @@ static int acpi_suspend_enter(suspend_state_t pm_state)
if (acpi_state == ACPI_STATE_S3)
acpi_restore_state_mem();

+ suspend_nvs_restore();
+
return ACPI_SUCCESS(status) ? 0 : -EFAULT;
}

@@ -583,12 +594,6 @@ static int acpi_hibernation_enter(void)
return ACPI_SUCCESS(status) ? 0 : -EFAULT;
}

-static void acpi_hibernation_finish(void)
-{
- suspend_nvs_free();
- acpi_pm_finish();
-}
-
static void acpi_hibernation_leave(void)
{
/*
@@ -626,7 +631,7 @@ static struct platform_hibernation_ops acpi_hibernation_ops = {
.begin = acpi_hibernation_begin,
.end = acpi_pm_end,
.pre_snapshot = acpi_hibernation_pre_snapshot,
- .finish = acpi_hibernation_finish,
+ .finish = acpi_pm_finish,
.prepare = acpi_pm_prepare,
.enter = acpi_hibernation_enter,
.leave = acpi_hibernation_leave,
@@ -679,7 +684,7 @@ static struct platform_hibernation_ops acpi_hibernation_ops_old = {
.begin = acpi_hibernation_begin_old,
.end = acpi_pm_end,
.pre_snapshot = acpi_hibernation_pre_snapshot_old,
- .finish = acpi_hibernation_finish,
+ .finish = acpi_pm_finish,
.prepare = acpi_pm_disable_gpes,
.enter = acpi_hibernation_enter,
.leave = acpi_hibernation_leave,
--
1.7.0.1