Re: 2.6.0-test5 atkbd.c: Unknown key (100% reproduceable)

From: Dmitri Katchalov
Date: Mon Sep 15 2003 - 08:49:09 EST


> On Sun, Sep 14, 2003 at 06:12:49PM +1000, Dmitri Katchalov wrote:
> > Quoting Andries Brouwer <aebr@xxxxxxxxxx>:
>
> > > On Sat, Sep 13, 2003 at 06:51:14PM +1000, Dmitri Katchalov wrote:
> > >
> > > > I'm consistently getting this error:
> > > >
> > > > atkbd.c: Unknown key (set 2, scancode 0xab, on isa0060/serio0)
pressed.
> > > > This happens whenever I type 'f' in "<F7>usbdevfs".
>
> It seems most likely that this keyboard is broken.
> Instead of 0xa1 (f release) you get 0xab (\ release).
> By some coincidence 0xab is f release in untranslated scancode set 2.
> (But you are in translated scancode set 2, otherwise the other letters
> would also have produced different codes.)
>
> Could you try to run "showkey -s" on the console under 2.4.*?
> Hit and release the f a few times. Type <F7>usbdevfs.
>
> Just a broken key is something I have seen lots of times.
> Since for most operating systems make codes are important
> while break codes (other than those for Shift, Ctrl, Alt)
> are not, a key with broken release code is usually harmless.
>
> This case seems interesting because, if I understand you correctly,
> the f in itself is not always broken, but this error occurs after
> a particular sequence of keystrokes.

I've just run showkey. This is WEIRD! I've never seen anything
like it (almost)! It is definitely a bug in my keyboard.
Whenever 'f' occurs in the stream exactly 12 scancodes
after <F7> it reports wrong release code. It even has a "queue"
so that multiple instances of the bug can be pipelined :)

Interestingly the bug has no ill effects on 2.4.18 at all. It just works.
In 2.6.0-test5 I'm getting a message right across the screen followed
by zillions of 'f's.

Andries, thanks for your time and for the hints you gave me. I'll put a
workaround in my kernel. I don't think it will be useful to anyone else
though:)

Regards,
Dmitri

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