PM / s2idle: Clear the events_check_enabled flag
[ Upstream commit 95b982b451
]
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>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
pull/10/head
parent
c4760b9c8d
commit
32f733a8f4
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@ -437,7 +437,6 @@ static int suspend_enter(suspend_state_t state, bool *wakeup)
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error = suspend_ops->enter(state);
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trace_suspend_resume(TPS("machine_suspend"),
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state, false);
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events_check_enabled = false;
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} else if (*wakeup) {
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error = -EBUSY;
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}
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@ -582,6 +581,7 @@ static int enter_state(suspend_state_t state)
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pm_restore_gfp_mask();
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Finish:
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events_check_enabled = false;
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pm_pr_dbg("Finishing wakeup.\n");
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suspend_finish();
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Unlock:
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