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PM / Wakeup: Make pm_save_wakeup_count() work as documented

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According to Documentation/ABI/testing/sysfs-power, the
/sys/power/wakeup_count interface should only make the kernel react
to wakeup events during suspend if the last write to it has been
successful.  However, if /sys/power/wakeup_count is written to two
times in a row, where the first write is successful and the second
is not, the kernel will still react to wakeup events during suspend
due to a bug in pm_save_wakeup_count().

Fix the bug by making pm_save_wakeup_count() clear
events_check_enabled unconditionally before checking if there are
any new wakeup events registered since the previous read from
/sys/power/wakeup_count.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
This commit is contained in:
Rafael J. Wysocki 2011-01-31 11:06:50 +01:00
parent 023d377914
commit 378eef99ad
1 changed files with 6 additions and 6 deletions
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12
drivers/base/power/wakeup.c
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@ -616,25 +616,25 @@ bool pm_get_wakeup_count(unsigned int *count)
* *
* If @count is equal to the current number of registered wakeup events and the * If @count is equal to the current number of registered wakeup events and the
* current number of wakeup events being processed is zero, store @count as the * current number of wakeup events being processed is zero, store @count as the
* old number of registered wakeup events to be used by pm_check_wakeup_events() * old number of registered wakeup events for pm_check_wakeup_events(), enable
* and return true. Otherwise return false. * wakeup events detection and return 'true'. Otherwise disable wakeup events
* detection and return 'false'.
*/ */
bool pm_save_wakeup_count(unsigned int count) bool pm_save_wakeup_count(unsigned int count)
{ {
unsigned int cnt, inpr; unsigned int cnt, inpr;
bool ret = false;
events_check_enabled = false;
spin_lock_irq(&events_lock); spin_lock_irq(&events_lock);
split_counters(&cnt, &inpr); split_counters(&cnt, &inpr);
if (cnt == count && inpr == 0) { if (cnt == count && inpr == 0) {
saved_count = count; saved_count = count;
events_check_enabled = true; events_check_enabled = true;
ret = true;
} }
spin_unlock_irq(&events_lock); spin_unlock_irq(&events_lock);
if (!ret) if (!events_check_enabled)
pm_wakeup_update_hit_counts(); pm_wakeup_update_hit_counts();
return ret; return events_check_enabled;
} }
static struct dentry *wakeup_sources_stats_dentry; static struct dentry *wakeup_sources_stats_dentry;