[linux-audio-user] debugging usb audio (silence from imic)

I've plugged a Griffin imic into my Dell 5150 (running FC3-ish). The machine recognised the card and modprobe snd-usb-audio, followed by alsamixer -c 1, showed the card. I can set and get the settings and the like all fine. The one thing I _can't_ get out is audio. None at all. aplay -device=hw:1,0 foofile.wav seems to run fine, except for the bit where it puts out sound. I've not got anything muted in alsamixer that I can see. This is kernel 2.6.8-1.541. (Hopefully) relevant bits from /proc/asound: bonanza# ls card0 cards I82801DBICH4 oss seq timers card1 devices modules pcm system version bonanza# cat cards 0 [I82801DBICH4 ]: ICH - Intel 82801DB-ICH4 Intel 82801DB-ICH4 at 0xf4fff800, irq 7 1 [system ]: USB-Audio - iMic USB audio system Griffin Technology, Inc iMic USB audio system at usb-0000:00:1d.0-1, full speed bonanza# cat version Advanced Linux Sound Architecture Driver Version 1.0.6 (Sun Aug 15 07:17:53 2004 UTC). Compiled on Sep 1 2004 for kernel 2.6.8-1.541. bonanza# cd card1 bonanza# ls id oss_mixer pcm0c pcm0p stream0 usbbus usbid bonanza# cat id system bonanza# cat stream0 # during 'aplay --device=hw:1,0 fooofile.wav' Griffin Technology, Inc iMic USB audio system at usb-0000:00:1d.0-1, full speed : USB Audio Playback: Status: Running Interface = 1 Altset = 2 URBs = 5 [ 4 4 4 4 4 ] Packet Size = 200 Momentary freq = 44100 Hz Interface 1 Altset 1 Format: S16_LE Channels: 1 Endpoint: 1 OUT (ADAPTIVE) Rates: 6400 - 48000 (continuous) Interface 1 Altset 2 Format: S16_LE Channels: 2 Endpoint: 1 OUT (ADAPTIVE) Rates: 6400 - 48000 (continuous) Capture: Status: Stop Interface 2 Altset 1 Format: S8 Channels: 1 Endpoint: 4 IN (SYNC) Rates: 6400 - 48000 (continuous) Interface 2 Altset 2 Format: S16_LE Channels: 1 Endpoint: 4 IN (SYNC) Rates: 6400 - 48000 (continuous) Interface 2 Altset 3 Format: S16_LE Channels: 2 Endpoint: 4 IN (SYNC) Rates: 6400 - 48000 (continuous) bonanza# lsmod | egrep 'snd|sound' snd_intel8x0 29709 0 snd_usb_audio 55457 1 snd_usb_lib 10305 1 snd_usb_audio snd_ac97_codec 61329 1 snd_intel8x0 snd_pcm_oss 42361 0 snd_mixer_oss 14529 1 snd_pcm_oss snd_pcm 84681 3 snd_intel8x0,snd_usb_audio,snd_pcm_oss snd_timer 25413 1 snd_pcm gameport 3777 1 snd_intel8x0 snd_mpu401_uart 7233 1 snd_intel8x0 snd_rawmidi 21733 2 snd_usb_lib,snd_mpu401_uart snd_seq_device 6217 1 snd_rawmidi snd 44709 11 snd_intel8x0,snd_usb_audio,snd_ac97_codec,snd_pcm_oss,snd_mixer_oss,snd_pcm,snd_timer,snd_mpu401_uart,snd_rawmidi,snd_seq_device soundcore 7457 1 snd snd_page_alloc 6985 2 snd_intel8x0,snd_pcm One thing I've noticed is that lsmod is telling me that the snd_usb_audio device is being used, but it's not saying _what_ it's being used by. I can't see any processes running that have anything in /dev/snd open. I'd love to get some tips on where to look next for continuing to debug this - one of my own projects is shtoom (a voip phone) and I'm always getting pleas for help with ALSA - it'd be excellent if I knew a bit more about what I'm doing here so I can help them in turn <wink> Thanks, Anthony