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author | Brian Norris <briannorris@chromium.org> | 2016-11-09 17:21:08 -0800 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-11-26 09:54:53 +0100 |
commit | 04c0800c73b23c74e70bf1a579dd383c26f823a0 (patch) | |
tree | 2fca04c0ea0d5bc4da03747ac1c22a7e72620412 | |
parent | 469fcbcb84d809ec05567d51f4fb664b894517e0 (diff) | |
download | emulator-kernel-04c0800c73b23c74e70bf1a579dd383c26f823a0.tar.gz emulator-kernel-04c0800c73b23c74e70bf1a579dd383c26f823a0.tar.bz2 emulator-kernel-04c0800c73b23c74e70bf1a579dd383c26f823a0.zip |
PM / sleep: don't suspend parent when async child suspend_{noirq, late} fails
commit 6f75c3fd56daf547d684127a7f83c283c3c160d1 upstream.
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 doing our error and wakeup checking
(particularly, for the async_error flag) after waiting for children to
suspend, instead of before. This also helps align the logic for the noirq and
late suspend cases with the logic in __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.)
Fixes: de377b397272 (PM / sleep: Asynchronous threads for suspend_late)
Fixes: 28b6fd6e3779 (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: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r-- | drivers/base/power/main.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c index ae60e6357d7b..e9b713675c7c 100644 --- a/drivers/base/power/main.c +++ b/drivers/base/power/main.c @@ -1022,6 +1022,8 @@ static int __device_suspend_noirq(struct device *dev, pm_message_t state, bool a TRACE_DEVICE(dev); TRACE_SUSPEND(0); + dpm_wait_for_children(dev, async); + if (async_error) goto Complete; @@ -1033,8 +1035,6 @@ static int __device_suspend_noirq(struct device *dev, pm_message_t state, bool a if (dev->power.syscore || dev->power.direct_complete) goto Complete; - dpm_wait_for_children(dev, async); - if (dev->pm_domain) { info = "noirq power domain "; callback = pm_noirq_op(&dev->pm_domain->ops, state); @@ -1169,6 +1169,8 @@ static int __device_suspend_late(struct device *dev, pm_message_t state, bool as __pm_runtime_disable(dev, false); + dpm_wait_for_children(dev, async); + if (async_error) goto Complete; @@ -1180,8 +1182,6 @@ static int __device_suspend_late(struct device *dev, pm_message_t state, bool as if (dev->power.syscore || dev->power.direct_complete) goto Complete; - dpm_wait_for_children(dev, async); - if (dev->pm_domain) { info = "late power domain "; callback = pm_late_early_op(&dev->pm_domain->ops, state); |