[linux-audio-user] Keyboard loss @ usb audio disconnect

Hans Fugal hans at fugal.net
Tue Nov 15 17:03:39 EST 2005

On Tue, 15 Nov 2005 at 21:00 +0100, Christoph Eckert wrote:
> Hi,
> > Not sure if I'm seeing the same problem, but it sounds like it might
> > be. My midi controller (keystation) works fine for day after day of
> > minimal use, and then one day I'll go to use it and it doesn't work.
> > qjackctl sees it and can establish connections, dmesg reports nothing
> > unusual. It just doesn't seem to be generating any events. I unplug
> > its usb and it disappears from qjackctl. I plug it back in and it
> > reappears, but still doesn't work. So I unplug the power and plug it
> > back in, same thing. So I unload snd-usb-audio and unplug the usb and
> > plug it back in and the same thing. Finally I give up and reboot.
> did you try amidimon in a shell window (amidimon --ports all) or 
> kmidimon to check if there realy is no MIDI coming in?

No, but I tried aseqview. I'll try one of those next time.

> In your case, maybe it's a problem of coldplug vs. hotplug. I'd try to 
> unplug the devices during boot time and plug it in after you logged in.
I think it is probably *plug related. I used to think that something in
the usb drivers was getting in a wierd state, but this last time being
able to fix it without a reboot is making me doubt that. Or it could
have been a coincidental unrelated problem.

> Furthermore, ensure that in your kernel config, drivers, usb you have 
> *disabled* usb-midi and usb-audio. Both are OSS and conflict with the 
> ALSA snd_usb_audio which handles four USB devices perfectly on my 
> machine (except for the keyboard loss, of course :) .

I'll double-check. Plugging and unplugging with snd-usb-audio works
great most of the time.
Hans Fugal ; http://hans.fugal.net
There's nothing remarkable about it. All one has to do is hit the 
right keys at the right time and the instrument plays itself.
    -- Johann Sebastian Bach
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