On 5/1/2025 4:17 PM, Mario Limonciello wrote:
From: Mario Limonciello <mario.limoncie...@amd.com>
Suspend and hibernate notifications are available specifically when
the sequence starts and finishes. However there are no notifications
during the process when tasks have been frozen.
Introduce two new events `PM_SUSPEND_POST_FREEZE` and
`PM_HIBERNATE_POST_FREEZE` that drivers can subscribe to and take
different actions specifically knowing userspace is frozen.
Suggested-by: Alex Deucher <alexander.deuc...@amd.com>
Signed-off-by: Mario Limonciello <mario.limoncie...@amd.com>
---
Documentation/driver-api/pm/notifiers.rst | 19 ++++++++++++++++---
include/linux/suspend.h | 14 ++++++++------
kernel/power/hibernate.c | 9 +++++++--
kernel/power/suspend.c | 13 +++++++++----
4 files changed, 40 insertions(+), 15 deletions(-)
diff --git a/Documentation/driver-api/pm/notifiers.rst
b/Documentation/driver-api/pm/notifiers.rst
index 186435c43b77e..6a1912fbee214 100644
--- a/Documentation/driver-api/pm/notifiers.rst
+++ b/Documentation/driver-api/pm/notifiers.rst
@@ -32,6 +32,18 @@ will be called upon the following events by the PM core:
additional work is done between the notifiers and the invocation of PM
callbacks for the "freeze" transition.
+``PM_HIBERNATION_POST_FREEZE``
+ The system is going to hibernate and tasks have just been frozen.
+
+``PM_SUSPEND_PREPARE``
+ The system is going to suspend, tasks will be frozen immediately. This
+ is different from ``PM_HIBERNATION_PREPARE`` above, because in this case
+ additional work is done between the notifiers and the invocation of PM
+ callbacks for the "freeze" transition.
I accidentally created this section ``PM_SUSPEND_PREPARE`` (there
already is one for PM_SUSPEND_PREPARE that is totally fine).
If conceptually the rest of the patch makes sense I will drop this section.
+
+``PM_SUSPEND_POST_FREEZE``
+ The system is going to suspend and tasks have just been frozen.
Looking again, I think this is better put between (the correct)
PM_SUSPEND_PREPARE and PM_POST_SUSPEND.
If conceptually the rest of the patch makes sense I will move it to that
section.
+
``PM_POST_HIBERNATION``
The system memory state has been restored from a hibernation image or an
error occurred during hibernation. Device restore callbacks have been
@@ -54,9 +66,10 @@ will be called upon the following events by the PM core:
resume callbacks have been executed and tasks have been thawed.
It is generally assumed that whatever the notifiers do for
-``PM_HIBERNATION_PREPARE``, should be undone for ``PM_POST_HIBERNATION``.
-Analogously, operations carried out for ``PM_SUSPEND_PREPARE`` should be
-reversed for ``PM_POST_SUSPEND``.
+``PM_HIBERNATION_PREPARE`` and ``PM_HIBERNATION_POST_FREEZE``, should be undone
+for ``PM_POST_HIBERNATION``.
+Analogously, operations carried out for ``PM_SUSPEND_PREPARE`` and
``PM_SUSPEND_POST_FREEZE``
+should be reversed for ``PM_POST_SUSPEND``.
Moreover, if one of the notifiers fails for the ``PM_HIBERNATION_PREPARE`` or
``PM_SUSPEND_PREPARE`` event, the notifiers that have already succeeded for
that
diff --git a/include/linux/suspend.h b/include/linux/suspend.h
index da6ebca3ff774..704e6579b0df6 100644
--- a/include/linux/suspend.h
+++ b/include/linux/suspend.h
@@ -422,12 +422,14 @@ static inline int is_hibernate_resume_dev(dev_t dev) {
return 0; }
#endif
/* Hibernation and suspend events */
-#define PM_HIBERNATION_PREPARE 0x0001 /* Going to hibernate */
-#define PM_POST_HIBERNATION 0x0002 /* Hibernation finished */
-#define PM_SUSPEND_PREPARE 0x0003 /* Going to suspend the system */
-#define PM_POST_SUSPEND 0x0004 /* Suspend finished */
-#define PM_RESTORE_PREPARE 0x0005 /* Going to restore a saved image */
-#define PM_POST_RESTORE 0x0006 /* Restore failed */
+#define PM_HIBERNATION_PREPARE 0x0001 /* Going to hibernate */
+#define PM_HIBERNATION_POST_FREEZE 0x0002 /* Prepared for hibernation and
tasks have been frozen */
+#define PM_POST_HIBERNATION 0x0003 /* Hibernation finished */
+#define PM_SUSPEND_PREPARE 0x0004 /* Going to suspend the system */
+#define PM_SUSPEND_POST_FREEZE 0x0005 /* Prepared and tasks have been
frozen */
+#define PM_POST_SUSPEND 0x0006 /* Suspend finished */
+#define PM_RESTORE_PREPARE 0x0007 /* Going to restore a saved
image */
+#define PM_POST_RESTORE 0x0008 /* Restore failed */
extern struct mutex system_transition_mutex;
diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index f0db9d1896e80..f896056ad2e5d 100644
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -783,11 +783,15 @@ int hibernate(void)
if (error)
goto Exit;
+ error = pm_notifier_call_chain_robust(PM_HIBERNATION_POST_FREEZE, PM_POST_HIBERNATION);
+ if (error)
+ goto Thaw;
+
lock_device_hotplug();
/* Allocate memory management structures */
error = create_basic_memory_bitmaps();
if (error)
- goto Thaw;
+ goto Unlock_hotplug;
error = hibernation_snapshot(hibernation_mode == HIBERNATION_PLATFORM);
if (error || freezer_test_done)
@@ -833,8 +837,9 @@ int hibernate(void)
Free_bitmaps:
free_basic_memory_bitmaps();
- Thaw:
+ Unlock_hotplug:
unlock_device_hotplug();
+ Thaw:
if (snapshot_test) {
pm_pr_dbg("Checking hibernation image\n");
error = swsusp_check(false);
diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
index 8eaec4ab121d4..bc6654e8cdc80 100644
--- a/kernel/power/suspend.c
+++ b/kernel/power/suspend.c
@@ -377,13 +377,18 @@ static int suspend_prepare(suspend_state_t state)
trace_suspend_resume(TPS("freeze_processes"), 0, true);
error = suspend_freeze_processes();
trace_suspend_resume(TPS("freeze_processes"), 0, false);
- if (!error)
- return 0;
+ if (error)
+ goto Restore;
+ error = pm_notifier_call_chain_robust(PM_SUSPEND_POST_FREEZE,
PM_POST_SUSPEND);
+ if (error)
+ goto Thaw;
- dpm_save_failed_step(SUSPEND_FREEZE);
- pm_notifier_call_chain(PM_POST_SUSPEND);
+ return 0;
+ Thaw:
+ suspend_thaw_processes();
Restore:
pm_restore_console();
+ dpm_save_failed_step(SUSPEND_FREEZE);
return error;
}
