On 24 June 2015 23:50:40 GMT+10:00, "Rafael J. Wysocki" <r...@rjwysocki.net> wrote: >On Wednesday, June 24, 2015 01:48:01 AM Preeti U Murthy wrote: >> On some archs, the local clockevent device stops in deep cpuidle >states. >> The broadcast framework is used to wakeup cpus in these idle states, >in >> which either an external clockevent device is used to send wakeup >ipis >> or the hrtimer broadcast framework kicks in in the absence of such a >> device. One cpu is nominated as the broadcast cpu and this cpu sends >> wakeup ipis to sleeping cpus at the appropriate time. This is the >> implementation in the oneshot mode of broadcast. >> >> In periodic mode of broadcast however, the presence of such cpuidle >> states results in the cpuidle driver calling tick_broadcast_enable() >> which shuts down the local clockevent devices of all the cpus and >> appoints the tick broadcast device as the clockevent device for each >of >> them. This works on those archs where the tick broadcast device is a >> real clockevent device. But on archs which depend on the hrtimer >mode >> of broadcast, the tick broadcast device hapens to be a pseudo device. >> The consequence is that the local clockevent devices of all cpus are >> shutdown and the kernel hangs at boot time in periodic mode. >> >> Let us thus not register the cpuidle states which have >> CPUIDLE_FLAG_TIMER_STOP flag set, on archs which depend on the >hrtimer >> mode of broadcast in periodic mode. This patch takes care of doing >this >> on powerpc. The cpus would not have entered into such deep cpuidle >> states in periodic mode on powerpc anyway. So there is no loss here. >> >> Signed-off-by: Preeti U Murthy <pre...@linux.vnet.ibm.com> > >4.2 material I suppose?
Yes please, in fact it should be marked for stable too. cheers -- Sent from my Android phone with K-9 Mail. Please excuse my brevity. _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
