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| author | Rajat Jain <rajatja@google.com> | 2017-10-31 14:44:24 -0700 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2017-11-08 23:52:02 +0100 |
| commit | 95b982b45122c57da2ee0b46cce70775e1d987af (patch) | |
| tree | 43598cf8b89db8c292043acec36d4732b99b9a6c | |
| parent | 0e708fc602531b8355b5de6ea7c98f09129b223f (diff) | |
| download | linux-95b982b45122c57da2ee0b46cce70775e1d987af.tar.bz2 | |
PM / s2idle: Clear the events_check_enabled flag
Problem: This flag does not get cleared currently in the suspend or
resume path in the following cases:
* In case some driver's suspend routine returns an error.
* Successful s2idle case
* etc?
Why is this a problem: What happens is that the next suspend attempt
could fail even though the user did not enable the flag by writing to
/sys/power/wakeup_count. This is 1 use case how the issue can be seen
(but similar use case with driver suspend failure can be thought of):
1. Read /sys/power/wakeup_count
2. echo count > /sys/power/wakeup_count
3. echo freeze > /sys/power/wakeup_count
4. Let the system suspend, and wakeup the system using some wake source
that calls pm_wakeup_event() e.g. power button or something.
5. Note that the combined wakeup count would be incremented due
to the pm_wakeup_event() in the resume path.
6. After resuming the events_check_enabled flag is still set.
At this point if the user attempts to freeze again (without writing to
/sys/power/wakeup_count), the suspend would fail even though there has
been no wake event since the past resume.
Address that by clearing the flag just before a resume is completed,
so that it is always cleared for the corner cases mentioned above.
Signed-off-by: Rajat Jain <rajatja@google.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
| -rw-r--r-- | kernel/power/suspend.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c index ccd2d20e6b06..0685c4499431 100644 --- a/kernel/power/suspend.c +++ b/kernel/power/suspend.c @@ -437,7 +437,6 @@ static int suspend_enter(suspend_state_t state, bool *wakeup) error = suspend_ops->enter(state); trace_suspend_resume(TPS("machine_suspend"), state, false); - events_check_enabled = false; } else if (*wakeup) { error = -EBUSY; } @@ -582,6 +581,7 @@ static int enter_state(suspend_state_t state) pm_restore_gfp_mask(); Finish: + events_check_enabled = false; pm_pr_dbg("Finishing wakeup.\n"); suspend_finish(); Unlock: |