Hi,
I'm having a PCMCIA card with USB and serial functionality. The USB
controller is OHCI based. And I've developed an OHCI driver for the
same. When I connect a "Philips Audio Speaker", and then play a ".wav"
file using the "play utility, I get the following message:
timeout: still 1 active urbs...
This message is printed by the audio driver module snd-usb-audio.ko.
And I receive this message only after the entire file is played.
Has anyone encountered this issue before?
I studied the audio driver code (usbaudio.c) and found the following:
1. In the completion handler, snd_complete_urb(), the following
condition is executed:
if ((subs->running && subs->ops.retire(subs, substream->runtime,
urb)) ||
! subs->running || /* can be stopped during retire callback
*/
(err = subs->ops.prepare(subs, substream->runtime, urb)) < 0
||
(err = usb_submit_urb(urb, GFP_ATOMIC)) < 0) {
clear_bit(ctx->index, &subs->active_mask);
if (err < 0) {
snd_printd(KERN_ERR "cannot submit urb (err =
%d)\n", err);
snd_pcm_stop(substream, SNDRV_PCM_STATE_XRUN);
}
}
2. On urb completion, this routine calls prepare_playback_urb
(ops.prepare in the above-mentioned condition) and then
submits the urb (usb_submit_urb). On a condition check,
prepare_playback_urb calls snd_usb_playback_trigger, which in
turn calls deactivate_urbs.
3. The function deactivate_urbs deactivates all the urbs (in my case,
no. of urbs is 8) using usb_unlink_urb. This function resets the
"subs->running" flag. So as per check, in the completion handler, no
completed urbs are resubmitted. However, in my case, one of the urbs,
which is completed has already checked this flag subs->running, and
hence this is resubmitted after ops.prepare returns.
4. This resubmitted urb after deactivate_urbs completes, results into 1
active urb remaining, therefore
audio driver prints the message from wait_clear_urbs function.
"timeout: still %d active urbs..\n"
Has anyone encountered this issue on OHCI before?
-Srivas
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