linux/kernel/power
Rajat Jain 95b982b451 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>
2017-11-08 23:52:02 +01:00
..
autosleep.c PM / Sleep: avoid 'autosleep' in shutdown progress 2013-07-15 01:31:37 +02:00
console.c PM / sleep: Make pm_prepare_console() return void 2016-06-15 01:26:04 +02:00
hibernate.c PM / sleep: Mark suspend/hibernation start and finish 2017-07-22 02:33:03 +02:00
Kconfig PM / sleep: Increase default DPM watchdog timeout to 120 2016-09-13 02:15:58 +02:00
main.c ACPI / PM: Check low power idle constraints for debug only 2017-08-18 01:54:22 +02:00
Makefile PM / Hibernate: Don't let kasan instrument snapshot.c 2016-06-14 00:38:56 +02:00
power.h ACPI / PM: Prefer suspend-to-idle over S3 on some systems 2017-08-05 01:51:26 +02:00
poweroff.c power/sysrq: fix inconstistent help message of sysrq key 2013-04-30 17:04:10 -07:00
process.c sched/cpuset/pm: Fix cpuset vs. suspend-resume bugs 2017-09-07 11:45:21 +02:00
qos.c PM: Use a more common logging style 2017-10-03 02:57:17 +02:00
snapshot.c PM: Use a more common logging style 2017-10-03 02:57:17 +02:00
suspend_test.c PM / s2idle: Rename PM_SUSPEND_FREEZE to PM_SUSPEND_TO_IDLE 2017-08-11 01:29:55 +02:00
suspend.c PM / s2idle: Clear the events_check_enabled flag 2017-11-08 23:52:02 +01:00
swap.c PM: Use a more common logging style 2017-10-03 02:57:17 +02:00
user.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
wakelock.c PM / autosleep: Use workqueue for user space wakeup sources garbage collector 2015-07-14 21:04:48 +02:00