kbdmux(4) freezing the system

Ulrich Spoerlein q at galgenberg.net
Thu Aug 25 21:26:41 GMT 2005

On Thu, 25.08.2005 at 14:12:04 -0700, Maksim Yevmenkin wrote:
> unfortunately its true. i was able to narrow it down on my system to
> ps/2 mouse and/or keyboard. basically if i use ps/2 mouse (and
> probably ps/2 keyboard) with kbdmux(4) i have system freeze. the
> solution that works for me is to _not_ use ps/2 mouse.

Well, I use the laptop keyboard (atkbd0) and either a PS2 keyboard via
PS2-USB convertor, or a SUN keyboard via SUN-USB converter (although,
the converter mumbles something about PS2)
addr 1: EHCI root hub, Intel
 addr 2: USB2.0 Hub, vendor 0x05e3
  addr 3: PS/2 KB & MS, vendor 0x0430

> you should also know that there is a keyboard state synchronization
> problem with kbdmux(4) (seems to be related to control/shift/alt keys)
> that i can reproduce, but still can not fix :(

Hmmm, I had something strange going on with this Sun keyboard. Namely,
all KeyPress/KeyRelease events would work like expected, except for the
two Meta keys. Pressing them, would do nothing. Releasing them would
result in the KeyPress (sic!) event. Then pressing any other key would
result in the KeyRelease of the Meta key *and* the KeyPress of the
pressed key.

I can't reproduce this since I'm no longer using kbdmux(4), but I also
changed my xmodmap, so this could be the cause.

> > So, are there any users of kbdmux out there? Are there any known
> > problems with system freezes? (I'm running RELENG_6 btw).
> i did not get much of a feedback, so i assume not many people are using it.

I think it's because it's not very easy to use. Getting that stupid
'kbdcontrol foo < /dev/whoknowswhatshouldbeplacedhere' right is very
tricky. Especially if you want it to work in rc.d/syscons and devd.conf.

> > I stopped using kbdmux(4) for now and not another freeze occurred, so it
> > strongly points to kbdmux being the culprit.
> yes, kbdmux(4) is definitely involved here. this is a high priority
> item on my todo list and as soon as i get enough free time i will look
> into this again.

Good, at least I know the culprit now and my mental sanity is saved :)
If you want me to test anything, just shoot.

Ulrich Spoerlein
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Ok, which part of "Ph'nglui mglw'nafh Cthulhu R'lyeh wgah'nagl fhtagn."
didn't you understand?
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