Re: my first usb-midi experiment ends with segmentation fault

[Takashi Iwai <tiwai@suse.de>]

At Sun, 28 Jul 2002 23:39:24 +0200,
Martin Langer wrote:
> 
> 
> Hi,
> 
> my new USB-MIDI-Keyboard has two USB subclasses usb-midi and usb-audio.
> Evolution, the manufacturer, told me "it's an Audio Class compliant device", 
> but I don't find a new entry in /proc/asound/seq/clients after loading the
> modules.
> 
> cat /proc/bus/usb/devices 
> 
> T:  Bus=01 Lev=01 Prnt=01 Port=00 Cnt=01 Dev#=  3 Spd=12  MxCh= 0
> D:  Ver= 1.00 Cls=01(audio) Sub=00 Prot=00 MxPS=64 #Cfgs=  1
> P:  Vendor=0a4d ProdID=008e Rev= 2.00
> S:  Manufacturer=Evolution Electronics Ltd.
> S:  Product=MK-249C USB MIDI keyboard
> C:* #Ifs= 2 Cfg#= 1 Atr=c0 MxPwr=  0mA
> I:  If#= 0 Alt= 0 #EPs= 0 Cls=01(audio) Sub=01 Prot=00 Driver=snd-usb-audio
> I:  If#= 1 Alt= 0 #EPs= 2 Cls=01(audio) Sub=03 Prot=00 Driver=snd-usb-midi
> E:  Ad=81(I) Atr=02(Bulk) MxPS=  64 Ivl=0ms
> E:  Ad=02(O) Atr=02(Bulk) MxPS=  64 Ivl=0ms
> 
> 
> dmesg:
> 
> usb.c: registered new driver snd-usb-audio
> usb.c: snd-usb-audio driver claimed interface dfe688c0
> usb.c: registered new driver snd-usb-midi
> snd-usb-midi: using interface 1
> snd-usb-midi: MIDIStreaming version 01.00
> snd-usb-midi: using 1 input jack(s) on endpoint 1
> snd-usb-midi: using 1 output jack(s) on endpoint 2
> snd-usb-midi: detected Evolution Electronics L MK-249C USB MIDI keyboa
> usb.c: snd-usb-midi driver claimed interface dfe688d8
> 
> 
> 
> It's not typical to have a midi-keyboard with two subclasses, or?

it's ok.
so far, audio and midi are implemented in separate ways.
yes, it would be nice if they are integrated, though.

> ... and doing rmmod snd-usb-midi and rmmod snd-usb-audio ends here with 
> Segmentation fault:
> 
> 
> Jul 28 22:28:07 tuba kernel: usb.c: deregistering driver snd-usb-audio
> Jul 28 22:28:10 tuba kernel: usb.c: deregistering driver snd-usb-midi
> Jul 28 22:28:10 tuba kernel: Unable to handle kernel paging request at
> virtual address 29323034
> Jul 28 22:28:10 tuba kernel:  printing eip:
> Jul 28 22:28:10 tuba kernel: e2858329
> Jul 28 22:28:10 tuba kernel: *pde = 00000000
> Jul 28 22:28:10 tuba kernel: Oops: 0002
> Jul 28 22:28:10 tuba kernel: CPU:    0
> Jul 28 22:28:10 tuba kernel: EIP:
> 0010:[snd-dt019x:__insmod_snd-dt019x_O/lib/modules/2.4.19-rc1/kernel/sound/i+-195799/96]

hmm, why snd-dt019x module appears here..?
was it loaded?  the trace seems corrupted...

could you try to put snd-usb-audio to /etc/hotplug/blacklist, so that
it's not automatically loaded.  then we'll know the problem is related
only with snd-usb-midi.


Takashi


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