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

["K.R. Foley" <kr@cybsft.com>]

Ingo Molnar wrote:
> * K.R. Foley <kr@cybsft.com> 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?
> 
> 
> 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.

I would like very much to come up with a condition that causes it. 
Unfortunately, the only event that I know of that is associated with 
this typing. :-) There does not seem to be a method to the madness.

As for bumping the priorities, I tried them all, at least the ones 
mentioned above. I also tried the timer just for grins, after changing 
the keyboard repeat delay seemed to help a bit. None of them seemed to 
help, at least not for an extended period of time.

> 
> 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?
> 

You may be on to something here. Booting with noapic SEEMS to help.

> 	Ingo
> 


-- 
    kr