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authorBrian Norris <briannorris@chromium.org>2016-11-09 17:21:08 -0800
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2016-11-11 01:29:09 +0100
commit6f75c3fd56daf547d684127a7f83c283c3c160d1 (patch)
treeb7c753c76fc7acd283895a25f0796bc27b86ba8f /tools
parentceb75787bc75d0a7b88519ab8a68067ac690f55a (diff)
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>
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