Open Sound System

I've built a usb soundcard around the pcm2902 ti burr-brown ic. It works like a charm in windows but I can't get it to work with oss.
It seems to be found and the right devices created (pcm0, mix0, pcmin0).

However if I try to playback I get the following errors in dmesg...

Without vmix:
Failed to set 44100 Hz sampling rate
oss_usb: Endpoint control write error -32

With vmix:
Failed to set 48000 Hz sampling rate
osscore: Trigger failed
oss_usb: Endpoint control write error -32

Any suggestions or pointers on how to go about this?

I've tried some more to get it working by using different play-alt values but the result remains the
same. I also tried to enable the trace and mixer options in the usb configuration file without success.

It seems that alsa should support this chip so I browsed their code for a while but I can't find any
quirks or the id 0x08bb 0x2902 in the source.

It seems that alsa should support this chip

Does it actually work with ALSA?

The error -32 indicates that the device refused the message, i.e., it did not want to switch to the specified sample rate.
According to the datasheet, this should not happen.

Yeah I gave alsa a try and it works.

Then it's a problem with the oss_usb driver.
I'd guess that the sequence of control request is somehow wrong.

Is there something I can do to help track down the problem?
I've noticed that there are some blocks of code which is disabled by #if 0 that seems to be able to generate some debuging output.

This is the information printed by the driver when enabling the disabled debug code.

Code: Select all

New audioctl device 1/0 - USB sound device
   Audio control interface header
   2 related streaming interfaces: 1 2
1: play  mix=4 target=3 ch=2/3 Input terminal type: 0101 Associated output 0x00 #chn 2 chconf 0003
2: output  mix=0 source=3 ch=2/3 Output terminal type: 0301 Associated input 0x00 sourceid 3
3: fea  source=1 target=2 ch=2/3 Source 1:play main (mute ) ch 1 (vol ) ch 2 (vol )
4: mic  mix=7 target=5 ch=2/3 Input terminal type: 0201 Associated output 0x00 #chn 2 chconf 0003
5: rec  mix=11 source=4 ch=2/3 Output terminal type: 0101 Associated input 0x00 sourceid 4
Ctl  0: 3/fea 0 Min 0, max 1, scale 1
ch=0 Value 0000, (0 - 1, 1)
Add (global) feature control 3:mute, max=1
Ctl  1: 3/fea 1 Min -32768, max 0, scale 255
ch=3 Value 4652, (-32768 - 0, 255)
Add feature control 3:vol
Unit 3
  Feature 3/2, ch 1: 00a9 (-22272) Min=0080 (-32768) max=0000 (0)
  Feature 3/2, ch 2: 00a3 (-23808) Min=0080 (-32768) max=0000 (0)
Another instance of '1'
New audio streaming device 1/1 - USB sound device
Trying to read altsetting 0
Trying to read altsetting 1
Altsetting 1, len 24
Select active setting 1 on interface 1 (dsp0)
Channels 2, bits 16 (2 bytes)
Format mask 00000010
Min rate 32000, max rate 48000
oss_usb: Endpoint control write error -32
Failed to set 48000 Hz sampling rate
osscore: Trigger failed
Another instance of '1'
New audio streaming device 1/2 - USB sound device
Trying to read altsetting 0
Trying to read altsetting 1
Altsetting 1, len 18
Select active setting 1 on interface 2 (dsp5)
Channels 2, bits 16 (2 bytes)
Format mask 00000010
Min rate 48000, max rate 48000
usbcore: registered new interface driver oss_usb
Audio device 5 not available when altsetting=0