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FROMLIST: PM / sleep: don't suspend parent when async child suspend_{noirq,late} fails

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Consider two devices, A and B, where B is a child of A, and B utilizes
asynchronous suspend (it does not matter whether A is sync or async). If
B fails to suspend_noirq() or suspend_late(), or is interrupted by a
wakeup (pm_wakeup_pending()), then it aborts and sets the async_error
variable. However, device A does not (immediately) check the async_error
variable; it may continue to run its own suspend_noirq()/suspend_late()
callback. This is bad.

We can resolve this problem by checking the async_error flag after
waiting for children to suspend, using the same logic for the noirq and
late suspend cases as we already do for __device_suspend().

It's easy to observe this erroneous behavior by, for example, forcing a
device to sleep a bit in its suspend_noirq() (to ensure the parent is
waiting for the child to complete), then return an error, and watch the
parent suspend_noirq() still get called. (Or similarly, fake a wakeup
event at the right (or is it wrong?) time.)

Change-Id: I9f6d9a599b45aaeb2debccc50a47525f138ad07e
Fixes: de377b3972 ("PM / sleep: Asynchronous threads for suspend_late")
Fixes: 28b6fd6e37 ("PM / sleep: Asynchronous threads for suspend_noirq")
Reported-by: Jeffy Chen <jeffy.chen@rock-chips.com>
Signed-off-by: Brian Norris <briannorris@chromium.org>
Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
This commit is contained in:
Brian Norris 2016-10-20 12:09:30 +08:00 committed by Shawn Lin
parent 82d6f6a314
commit 11b2dcefd8
1 changed files with 6 additions and 0 deletions
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6
drivers/base/power/main.c
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@ -1038,6 +1038,9 @@ static int __device_suspend_noirq(struct device *dev, pm_message_t state, bool a
dpm_wait_for_children(dev, async);
if (async_error)
goto Complete;
if (dev->pm_domain) {
info = "noirq power domain ";
callback = pm_noirq_op(&dev->pm_domain->ops, state);
@ -1185,6 +1188,9 @@ static int __device_suspend_late(struct device *dev, pm_message_t state, bool as
dpm_wait_for_children(dev, async);
if (async_error)
goto Complete;
if (dev->pm_domain) {
info = "late power domain ";
callback = pm_late_early_op(&dev->pm_domain->ops, state);