On Wednesday, July 01, 2015 12:52:43 AM Nitish Ambastha wrote: > Hi Rafael > > Thanks for your feedback > > On Tue, Jun 30, 2015 at 1:37 AM, Rafael J. Wysocki <r...@rjwysocki.net> wrote: > > On Monday, June 29, 2015 09:56:18 PM Rafael J. Wysocki wrote: > >> On Tuesday, June 30, 2015 12:24:14 AM Nitish Ambastha wrote: > >> > Prevent tight loop for suspend-resume when some > >> > devices failed to suspend > >> > If some devices failed to suspend, we monitor this > >> > error in try_to_suspend(). pm_suspend() is already > >> > an 'int' returning function, how about checking return > >> > from pm_suspend() before queueing suspend again? > >> > > >> > For devices which do not register for pending events, > >> > this will prevent tight loop for suspend-resume in > >> > suspend abort scenarios due to device suspend failures > > > > Having said the below I'm not sure why the current code doesn't cover this > > for you? > > > > That would be the final_count == initial_count case, no? > > > Agree, this should cover most of the cases, however there are some > cases where final_count may not match initial_count here > > A couple of such scenario I came across is > 1) when tasks are restarted again due to suspend failure, sometimes > battery kernel thread acquires lock for battery monitoring resulting > in either pm_get_wakeup_count() returning false or increment in > final_count from initial_count
Locks should not have any effect on the return value of pm_get_wakeup_count() and if false is returned by it, a wakeup event was being processed when it was called. In turn, if pm_get_wakeup_count() returns false or final_count != initial_count, this means that *somebody* called pm_wakeup_event() or equivalent in the meantime and there *was* a valid wakeup event (regardless of or in addition to the driver error). > 2) In some platforms, power transitions are carried from User space > (power manager), these power-manager tries to hold some wake lock > after being restarted on resume And what exactly is the failing scenario in that case? -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
