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#1 2005-08-21 11:34:34

starthis
Member
Registered: 2004-12-25
Posts: 45

usbaudio troubles

I have an usbphone device to play with (I want to use it for skype), but it seems getting this to work in archlinux wasn't as trivial as in other distro's.

The needed modules seemed to load fine when the device was plugged in.
(snd_usb_audio, snd_usb_lib)
The dmesg output seemed ok too :

usb 1-4: new full speed USB device using ohci_hcd and address 5
usbaudio: device 5 audiocontrol interface 0 has 1 input and 1 output AudioStreaming interfaces
usbaudio: valid input sample rate 8000
usbaudio: valid input sample rate 48000
usbaudio: valid input sample rate 44100
usbaudio: valid input sample rate 22050
usbaudio: valid input sample rate 11025
usbaudio: device 5 interface 2 altsetting 1: format 0x00000010 sratelo 8000 sratehi 48000 attributes 0x01
usbaudio: valid output sample rate 8000
usbaudio: valid output sample rate 48000
usbaudio: valid output sample rate 44100
usbaudio: valid output sample rate 22050
usbaudio: valid output sample rate 11025
usbaudio: device 5 interface 1 altsetting 1: format 0x80000010 sratelo 8000 sratehi 48000 attributes 0x01
usbaudio: registered dsp 14,3
usbaudio: constructing mixer for Terminal 8 type 0x0301
usbaudio: registered mixer 14,0
usbaudio: constructing mixer for Terminal 12 type 0x0101
usbaudio: registered mixer 14,16
usb_audio_parsecontrol: usb_audio_state at f7027dc0
input: USB HID v1.00 Device [??Welltech Computer K1000A] on usb-0000:00:02.0-4

Unfortunatly, I was unable to use the device, and I couldn't access its mixer through ALSA...

After alot of reading in the ALSA faq's I read a comment that said it was important that the 'audio' module wasn't loaded, or it would prevent snd_usb_audio from accessing the usbdevice.
When I rmmod audio, and then plugin the usb audio device, I can access the device as hw 2,0 and access its mixer through ALSA smile
Alas that putting !audio in rc.conf modules doesn't prevent the audio module from loading. So I have to do it manually everytime. Any ideas why this is the case?

Besides this little problem, I noticed the ALSA hardware mixer for the device doesn't actually work. But this is probably device dependant problem.

Getting skype to work with the device is a disaster too, since it doesn't support ALSA natively.

xmms, mplayer work with the device perfectly. So playback is fine. Recording on the otherhand doesn't work either. If I start gnome sound recorder it just hangs, totem hangs, audacity doesn't find any recording device, ... Anybody encountered simular issues with usbaudio devices?

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#2 2005-08-21 13:13:35

tomk
Forum Fellow
From: Ireland
Registered: 2004-07-21
Posts: 9,835

Re: usbaudio troubles

starthis wrote:

Alas that putting !audio in rc.conf modules doesn't prevent the audio module from loading. So I have to do it manually everytime. Any ideas why this is the case?

Putting !audio in rc.conf MODULES means that Arch's init scripts won't load the module - it doesn't prevent the module from being loaded some other way. In this case, I'd say it's hotplug that's doing it, so add audio to /etc/hotplug/blacklist and that part of your problem should be OK.

I've never used usbaudio, so I can't help you with the rest.

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#3 2005-08-21 14:53:38

starthis
Member
Registered: 2004-12-25
Posts: 45

Re: usbaudio troubles

I never checked the blacklist until now, and to my supprise I find the following lines there :

audio           # ADDED_BY_OSS
snd_usb_audio   # ADDED_BY_OSS
snd-usb-audio   # ADDED_BY_OSS

So both audio and snd_usb_audio are blacklisted, still they are loaded. Can I assume its not hotplug but something else that loads the audio module? If so, what is?  :shock:

The snd_usb_audio is loaded at the time of plugging in the device, the audio module on the other hand is already there after booting.

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#4 2005-08-21 21:53:42

tomk
Forum Fellow
From: Ireland
Registered: 2004-07-21
Posts: 9,835

Re: usbaudio troubles

OK, I have two more ideas, one of which is good  lol

The audio module is part of the old OSS sound system, which you don't need, so you could compile your own kernel without OSS, and the module will no longer exist.

If you don't feel like the kernel thing, then there's my second idea - this is very definitely not the good one. Anyway, I had a look at my own hotplug blacklist, and noticed that it said

Syntax:  driver name alone (without any spaces) on a line.

and sure enough, any modules on my blacklist conform to that. Now yours, on the other hand, have

# ADDED_BY_OSS

after them. I know it's commented, but the syntax requirement is "driver name ALONE on a line", so it might be worth a shot?

Well, I did say it wasn't a good idea. Me, I'd do a new kernel - there's some good stuff in the wiki about it, if you're interested.

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#5 2005-08-22 19:18:50

starthis
Member
Registered: 2004-12-25
Posts: 45

Re: usbaudio troubles

Thanks for the ideas tomk smile

your last idea was actually quite right. Removing the comments behind it stops loading the audio module.

And then the snd_usb_audio loads ok.
Since I never edited the blacklist myself, I can only guess I ran some OSS config that commented the lines out in the blacklist. Though it would of been much clearer if they put the # in front of the line :shock:

I rebuild my kernel anyway from time to time since I have an ATI gfxcard, so will leave out OSS in the future builds.

With the audio module out of the way, everything seems to work smooth! The usbaudio sky is clear for me wink

With little trouble I also managed to get the usbphone to work with skype (oss only)

Only remaining issue is that I the playback/recording mixers (alsa and oss) don't work. One step at a time I guess wink

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