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

Christoph Eckert ce at christeck.de
Sat Nov 12 19:40:54 EST 2005

Hi all,

I'd be glad to hear any comments on the following annoying problem. If 
we could locate and eliminate the reason for this bug, this would be 

I have various USB audio/midi devices:

* Midisport 8x8
* Terratec Aureon USB
* m-audio Trigger Finger

Not always but often when I disconnect them from my machine, I loose my 
keyboard so I have to restart the machine. During the shutdown, the 
machine hangs when shutting down hotplug.

After the reboot, some hardware is still messed, e.g. no DSL connection 
can be established. I have to reboot the machine again, then it works.

I tried to monitor the messages-log and the xorg-log but I got no 
valuable information. I see the following misbehaviours:

* No keyboard at all
* Konsole (the KDE console emulation) cannot be closed. It hangs
* The machine hangs at shutdown when trying to stop hotplug. I see a 
kernel Ooops, and it reports a segfaut.

see http://www.christeck.de/files/DSCN1061.JPG
for details.

A thing that all used devices share is that they do not register 
properly on the USB bus. Instead of registering as usb audio devices, 
these register as HID (human input device) or similar on the bus.

The question is:

* Anyone else having this behaviour?
* Does anyone have a clue which software (hotplug, X.org, KDE) causes 
the keyboard disconnect?
* Any hints which other software components can cause this?

I'd be very glad if we could find the reason for this behaviour and 
report it to the responsible project so the devices can be 
blacklisteted  there.

Thanks & best regards


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