# \[PATCH v2\] PM: sleep: core: Avoid setting power.must\_resume to false - From: Prasad Sodagudi \ - Date: 2021-08-08 16:10:42 - List: linux-pm - Page: https://ratatoskr.run/linux-pm/2021/08/1471258 - Thread: https://ratatoskr.run/linux-pm/2021/07/1457648/t.md ```text There are variables(power.may_skip_resume and dev->power.must_resume) and DPM_FLAG_MAY_SKIP_RESUME flags to control the resume of devices after a system wide suspend transition. Setting the DPM_FLAG_MAY_SKIP_RESUME flag means that the driver allows its "noirq" and "early" resume callbacks to be skipped if the device can be left in suspend after a system-wide transition into the working state. PM core determines that the driver's "noirq" and "early" resume callbacks should be skipped or not with dev_pm_skip_resume() function by checking power.may_skip_resume variable. power.must_resume variable is getting set to false in __device_suspend() function without checking device's DPM_FLAG_MAY_SKIP_RESUME and dev->power.usage_count variables. In problematic scenario, where all the devices in the suspend_late stage are successful and some device can fail to suspend in suspend_noirq phase. So some devices successfully suspended in suspend_late stage are not getting chance to execute __device_suspend_noirq() to set dev->power.must_resume variable to true and not getting resumed in early_resume phase. Add a check for device's DPM_FLAG_MAY_SKIP_RESUME flag before setting power.must_resume variable in __device_suspend function. Fixes: 6e176bf8d461 ("PM: sleep: core: Do not skip callbacks in the resume phase") Signed-off-by: Prasad Sodagudi --- drivers/base/power/main.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c index d568772..9ee6987 100644 --- a/drivers/base/power/main.c +++ b/drivers/base/power/main.c @@ -1642,7 +1642,11 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async) } dev->power.may_skip_resume = true; - dev->power.must_resume = false; + if ((atomic_read(&dev->power.usage_count) <= 1) && + (dev_pm_test_driver_flags(dev, DPM_FLAG_MAY_SKIP_RESUME))) + dev->power.must_resume = false; + else + dev->power.must_resume = true; dpm_watchdog_set(&wd, dev); device_lock(dev); -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project ```