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@xxxxxxxxxx> Signed-off-by: Maxim Levitsky <maximlevitsky@xxxxxxxxx> --- drivers/acpi/sleep.c | 14 ++++++++++++-- 1 files changed, 12 insertions(+), 2 deletions(-) diff --git a/drivers/acpi/sleep.c b/drivers/acpi/sleep.c index bdb306f..5d26d8e 100644 --- a/drivers/acpi/sleep.c +++ b/drivers/acpi/sleep.c @@ -114,6 +114,8 @@ 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; @@ -143,6 +145,8 @@ static void acpi_pm_finish(void) { u32 acpi_state = acpi_target_sleep_state; + suspend_nvs_free(); + if (acpi_state == ACPI_STATE_S0) return; @@ -192,6 +196,11 @@ 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); @@ -269,6 +278,8 @@ 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; } @@ -443,7 +454,6 @@ static int acpi_hibernation_enter(void) static void acpi_hibernation_finish(void) { - suspend_nvs_free(); acpi_ec_unblock_transactions(); acpi_pm_finish(); } @@ -479,7 +489,7 @@ 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, -- 1.7.0.4 _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
