Re: snd-usb-audio and midisport1x1 little hack fixes hotplug pb

[Takashi Iwai <tiwai@suse.de>]

At Sat, 13 Mar 2004 04:32:34 +0100,
Mathieu Geli wrote:
> 
> Ok, I applied your second patch, and get this dmesg output:
> 
> drivers/usb/core/usb.c: deregistering driver snd-usb-audio
> ALSA /home/mathieu/alsa-driver/usb/usbaudio.c:2944: snd_usb_audio_disconnect called, refcount = 1
> ALSA /home/mathieu/alsa-driver/usb/usbaudio.c:2944: snd_usb_audio_disconnect called, refcount = 0
> ALSA /home/mathieu/alsa-driver/alsa-kernel/usb/usbmidi.c:148: urb status -104
> ALSA /home/mathieu/alsa-driver/alsa-kernel/usb/usbmidi.c:134: usb_submit_urb: -32

this means that the urbs are still active.  i'm not sure whether these
messages appear after or before calling snd_usbmidi_disconnect(),
though.

> At this point the usb was down not responding anymore, like in the past.
> 
> what I did next, is put double each interesting lines printk, what I
> get is, that the rmmod of the driver was hanging on the midi
> ressources cleaning stuff. 
> Hum, first reflex: I just comment out those 3 lines =) and guess
> what.. that works fine now. I tried to plug/unplug several times my
> mouse, the midisport, and everything 
> works fine, so... I don't really know what was the bug's reason, but
> as long as that works I'm happy ;-) 

i also don't know yet why disconnect() call hangs up.
could you check at which point it happens by adding printk()'s in
snd_usbmidi_disconnect()?

the resource release can work even without disconnect() call, since
the clean up will be done later also by the workqueue when all devices
are closed properly.  the disconnect function should shut up possible
hardware features immediately.


Takashi


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