From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> On systems with ACPI platform firmware the last stage of hibernation is analogous to system suspend to S3 (suspend-to-RAM), so it should be handled analogously. In particular, pm_suspend_via_firmware() should return 'true' in that stage to let the callers of it know that control will be passed to the platform firmware going forward, so pm_set_suspend_via_firmware() needs to be called then in analogy with acpi_suspend_begin(). However, the platform hibernation ->begin() callback is invoked during the "freeze" transition (before creating a snapshot image of system memory) as well as during the "hibernate" transition which is the last stage of it and pm_set_suspend_via_firmware() should be invoked by that callback in the latter stage only. In order to implement that redefine the hibernation ->begin() callback to take a pm_message_t argument to indicate which stage of hibernation is taking place and rework acpi_hibernation_begin() and acpi_hibernation_begin_old() to take it into account as needed. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> --- drivers/acpi/sleep.c | 39 ++++++++++++++++++++++++--------------- include/linux/suspend.h | 2 +- kernel/power/hibernate.c | 4 ++-- 3 files changed, 27 insertions(+), 18 deletions(-) Index: linux-pm/include/linux/suspend.h =================================================================== --- linux-pm.orig/include/linux/suspend.h +++ linux-pm/include/linux/suspend.h @@ -359,7 +359,7 @@ extern void mark_free_pages(struct zone * platforms which require special recovery actions in that situation. */ struct platform_hibernation_ops { - int (*begin)(void); + int (*begin)(pm_message_t stage); void (*end)(void); int (*pre_snapshot)(void); void (*finish)(void); Index: linux-pm/kernel/power/hibernate.c =================================================================== --- linux-pm.orig/kernel/power/hibernate.c +++ linux-pm/kernel/power/hibernate.c @@ -129,7 +129,7 @@ static int hibernation_test(int level) { static int platform_begin(int platform_mode) { return (platform_mode && hibernation_ops) ? - hibernation_ops->begin() : 0; + hibernation_ops->begin(PMSG_FREEZE) : 0; } /** @@ -542,7 +542,7 @@ int hibernation_platform_enter(void) * hibernation_ops->finish() before saving the image, so we should let * the firmware know that we're going to enter the sleep state after all */ - error = hibernation_ops->begin(); + error = hibernation_ops->begin(PMSG_HIBERNATE); if (error) goto Close; Index: linux-pm/drivers/acpi/sleep.c =================================================================== --- linux-pm.orig/drivers/acpi/sleep.c +++ linux-pm/drivers/acpi/sleep.c @@ -1128,15 +1128,19 @@ void __init acpi_no_s4_hw_signature(void nosigcheck = true; } -static int acpi_hibernation_begin(void) +static int acpi_hibernation_begin(pm_message_t stage) { - int error; + if (!nvs_nosave) { + int error = suspend_nvs_alloc(); + if (error) + return error; + } - error = nvs_nosave ? 0 : suspend_nvs_alloc(); - if (!error) - acpi_pm_start(ACPI_STATE_S4); + if (stage.event == PM_EVENT_HIBERNATE) + pm_set_suspend_via_firmware(); - return error; + acpi_pm_start(ACPI_STATE_S4); + return 0; } static int acpi_hibernation_enter(void) @@ -1196,7 +1200,7 @@ static const struct platform_hibernation * function is used if the pre-ACPI 2.0 suspend ordering has been * requested. */ -static int acpi_hibernation_begin_old(void) +static int acpi_hibernation_begin_old(pm_message_t stage) { int error; /* @@ -1207,16 +1211,21 @@ static int acpi_hibernation_begin_old(vo acpi_sleep_tts_switch(ACPI_STATE_S4); error = acpi_sleep_prepare(ACPI_STATE_S4); + if (error) + return error; - if (!error) { - if (!nvs_nosave) - error = suspend_nvs_alloc(); - if (!error) { - acpi_target_sleep_state = ACPI_STATE_S4; - acpi_scan_lock_acquire(); - } + if (!nvs_nosave) { + error = suspend_nvs_alloc(); + if (error) + return error; } - return error; + + if (stage.event == PM_EVENT_HIBERNATE) + pm_set_suspend_via_firmware(); + + acpi_target_sleep_state = ACPI_STATE_S4; + acpi_scan_lock_acquire(); + return 0; } /*