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author | Brian Norris <briannorris@chromium.org> | 2016-11-10 01:21:08 (GMT) |
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committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2016-11-11 00:29:09 (GMT) |
commit | 6f75c3fd56daf547d684127a7f83c283c3c160d1 (patch) | |
tree | b7c753c76fc7acd283895a25f0796bc27b86ba8f /kernel | |
parent | ceb75787bc75d0a7b88519ab8a68067ac690f55a (diff) | |
download | linux-6f75c3fd56daf547d684127a7f83c283c3c160d1.tar.xz |
PM / sleep: don't suspend parent when async child suspend_{noirq, late} fails
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>
Diffstat (limited to 'kernel')
0 files changed, 0 insertions, 0 deletions