Messages in this thread | | | Subject | Re: TSC not updating after resume: Bug or Feature? | From | Peter Zijlstra <> | Date | Fri, 26 Dec 2008 09:47:21 +0100 |
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On Wed, 2008-12-24 at 15:09 +0100, Pavel Machek wrote: > Hi! > > > > > > > > Can please you revert the last patch and apply the following ? Does > > > > the WARN_ON trigger ? > > > > > > > > > Yes, it does: > > > > > [ 159.768005] [<c01389a2>] getnstimeofday+0x21/0xcd > > > [ 159.768005] [<c0135e26>] ktime_get_ts+0x1d/0x3f > > > [ 159.768005] [<c0135e57>] ktime_get+0xf/0x2b > > > [ 159.768005] [<c013736b>] sched_clock_tick+0x46/0x83 > > > [ 159.768005] [<c01373ad>] sched_clock_idle_wakeup_event+0x5/0xa > > > [ 159.768005] [<c0108670>] set_cyc2ns_scale+0x3f/0x5e > > > [ 159.768005] [<c01088af>] time_cpufreq_notifier+0xf9/0x103 > > > [ 159.768005] [<c0136782>] notifier_call_chain+0x2a/0x52 > > > [ 159.768005] [<c0136866>] __srcu_notifier_call_chain+0x35/0x4a > > > [ 159.768005] [<c0136884>] srcu_notifier_call_chain+0x9/0xc > > > [ 159.768005] [<c031cbca>] cpufreq_resume+0xf3/0x112 > > > [ 159.768005] [<c028c3f3>] __sysdev_resume+0x24/0x34 > > > [ 159.768005] [<c028c421>] sysdev_resume+0x1e/0x50 > > > > Thanks for testing. It's exaclty the code path I described :) > > > > So my code analysis holds and your test confirms my suspicion that > > Shaggy's patch just unearthed some other weirdness in the > > suspend/resume code. > > > > Can you please apply the following hack^Wpatch and retest ? It > > restores Shaggys patch, but prevents the sched_clock_tick() call when > > timekeeping is not resumed. The WARN_ON should not longer trigger > > except there is some other code path which fiddles with that as well. > > > > If I'm not completely nuts then this should solve your suspend/resume > > problem really instead of papering over the root cause. > > Should we move timekeeping resume before cpufreq resume, instead of this?
That seems a sensible suggestion (but I've got no clue on how practical that is). A quick look at the boot code suggests that regular bootups have that sequence as well, so mirroring that in the resume code seems like the best all-round solution.
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