ACPI: Store NVS state even when entering suspend to RAM
Matthew Garrett [Fri, 28 May 2010 20:32:15 +0000 (16:32 -0400)]
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>
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/acpi/sleep.c

index bcaa6ef..403daf0 100644 (file)
@@ -112,6 +112,8 @@ 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;
@@ -140,6 +142,8 @@ static void acpi_pm_finish(void)
 {
        u32 acpi_state = acpi_target_sleep_state;
 
+       suspend_nvs_free();
+
        if (acpi_state == ACPI_STATE_S0)
                return;
 
@@ -189,6 +193,11 @@ 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);
@@ -264,6 +273,8 @@ 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;
 }
 
@@ -430,12 +441,6 @@ 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)
 {
        /*
@@ -473,7 +478,7 @@ 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,
@@ -526,7 +531,7 @@ 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,