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Commit 2a6b6976 authored by Matthew Garrett's avatar Matthew Garrett Committed by Len Brown
Browse files

ACPI: Store NVS state even when entering suspend to RAM 

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: default avatarMatthew Garrett <mjg@redhat.com>
Signed-off-by: default avatarLen Brown <len.brown@intel.com>
parent dd4c4f17

drivers/acpi/sleep.c

+13 −8
Original line number Diff line number Diff line
@@ -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,