[PATCH] ACPI: PM: Call pm_set_suspend_via_firmware() during hibernation

Rafael J. Wysocki
2019-05-16T10:43:23Z

From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

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@intel.com>
---
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;
}

/*