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由 Brian Norris 提交于
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: de377b39 (PM / sleep: Asynchronous threads for suspend_late) Fixes: 28b6fd6e (PM / sleep: Asynchronous threads for suspend_noirq) Reported-by: NJeffy Chen <jeffy.chen@rock-chips.com> Signed-off-by: NBrian Norris <briannorris@chromium.org> Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
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