On Tue, 19 Jul 2016, Chen Yu wrote: > It is reported the hibernation fails at 2nd attempt, which > hangs at hibernate() -> syscore_resume() -> i8237A_resume() > -> claim_dma_lock(), because the lock has already been taken. > However there is actually no other process would like to grab > this lock on that problematic platform. > > Further investigation shows that, the problem is caused by setting > /sys/power/pm_trace to 1 before the 1st hibernation, since once > pm_trace is enabled, the rtc becomes an unmeaningful value after resumed, So why is the RTC value useless if pm_trace is enabled? I really have a hard time to understand why pm_trace would affect the sleep time readout from RTC. Thanks, tglx -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html