Messages in this thread | | | Subject | Re: Keyboard Stuttering | From | john stultz <> | Date | Tue, 10 Oct 2006 11:25:14 -0700 |
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On Tue, 2006-10-10 at 13:09 -0400, Dmitry Torokhov wrote: > On 10/6/06, David Gerber <dg-lkml@zapek.com> wrote: > > > I'm experiencing some severe keyboard stuttering on my laptop. The > > > problem is particularly bad in X, and I believe it also occurs at the > > > console, though I'm having a difficult time verifying that. The problem > > > shows up as repeated characters (not regular key-repeat-related), and > > > sometimes dropped key presses. > > > > (I'm not subscribed to the list, CC: to me if needed) > > > > Same problem here. Intel Core 2 Duo with 2.6.19-rc1 x86_64 SMP. Happens on > > 2.6.17 too. I use 'noapic' as a workaround but that disables one of the CPU > > core of course. > > > > I cannot reproduce the problem within the console nor gdm. Only on the X > > desktop. > > > > John, > > It looks like the only clocksource available on David's box is > "jiffies" although the processor shows that it supporst tsc and PM > timer is enabled and I think that this is what causes keyboard > stuttering in X. See http://bugzilla.kernel.org/show_bug.cgi?id=7291. > I believe clocksources is your turf, could you please take a look at > this.
Sure thing. I followed up in the bug, but I don't think the clocksource code is involved. x86_64 hasn't converted to GENERIC_TIME, so jiffies is what we use to increment xtime, but the TSC, ACPI PM, or HPET is used for gettimeofday, etc.
I suspect C3 idling is the culprit, since noapic works around the issue.
thanks -john
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