On Tue 04-12-18 10:33:10, Ingo Molnar wrote: > > * Michal Hocko <mho...@kernel.org> wrote: > > > I dunno. I do not use hibernation. I am a heavy user of the suspend > > though. I s2ram all the time. And I have certainly experienced cases > > where suspend has failed and I onlyi found out later when I've picked > > up my laptop from my heat up bag. Nothing fatal has resulted from that > > but this is certainly annoying. > > Hm, so I (mistakenly) thought freezing was mostly limited to hibernation > and to a few weird cases when in flight DMA must not be suspended - but > I'm wrong and in practice we always freeze tasks during s2ram, right?
Yup. > And indeed: > > config SUSPEND_FREEZER > bool "Enable freezer for suspend to RAM/standby" \ > if ARCH_WANTS_FREEZER_CONTROL || BROKEN > depends on SUSPEND > default y > > which is essentially always enabled on x86. > > TIL ... > > s2ram is obviously a huge deal. > > Just a newbie question: any chance to not do any freezing at all on > modern laptops when doing s2ram, or at least only warn if it fails and > try to suspend? AFAIU both suspend and hibernation require the system to enter quiescent state with no task potentially interfering with suspended devices. And in this particular case those de-thread-ed threads will certainly not interfere so silencing the lockdep sounds like a reasonable workaround. -- Michal Hocko SUSE Labs