Re: Real-Time Preemption -RT-V0.7.51-17 - Keyboard Problems

[K.R. Foley]

Doug Maxey wrote:
> On Fri, 08 Jul 2005 21:13:26 +0200, Ingo Molnar wrote:
>
> > * K.R. Foley <kr@xxxxxxxxxx> wrote:
> >
> >
> > > Ingo,
> > >
> > > I have an issue with keys VERY SPORADICALLY repeating, SOMETIMES, when 
> > > running the RT patches. The problem manifests itself as if the key 
> > > were stuck but happens far too quickly for that to be the case. I 
> > > realize that the statements above are far from scientific, but I can't 
> > > seem to narrow it down further. 2.6.12 doesn't seem to have the 
> > > problem at all, only when running the RT patches. It SEEMS to have 
> > > gotten worse lately. I am attaching my config as well as the output 
> > > from lspci.
> > >
> > > Adjusting the delay in the keyboard repeat seems to help. Any ideas?
>
>
> Is the keyboard standard (PS2) or USB?  Did not see the detail.

Sorry. It is PS2.

> > hm. Would be nice to somehow find a condition that triggers it. One 
> > possibility is that something else is starving the keyboard handling 
> > path. Right now it's handled via workqueues, which live in keventd. Do 
> > things improve if you chrt keventd up to prio 99? Also i'd chrt the 
> > keyboard IRQ thread up to prio 99 too.
> >
> > the other possibility is some IRQ handling bug - those are usually 
> > specific to the IRQ controller, so try turning off (or on) the IO-APIC 
> > [if the box has an IO-APIC], does that change anything?
>
>
> FWIW, I have seen this issue under USB, off and on since about 2.6.9.
> Never have dug into it, was always simpler to just unplug and re-plug
> the keyboard.  Of course, this predates RT.
>
> ++doug


--
   kr
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