[alsa-devel] [PATCH 2/5] ALSA: snd-usb: switch over to new endpoint streaming logic

[Clemens Ladisch]

On 10/31/2011 01:10 PM, Daniel Mack wrote:
> @@ -276,6 +312,15 @@ static int set_format(struct snd_usb_substream *subs, struct audioformat *fmt)
>  	if (((is_playback && attr == USB_ENDPOINT_SYNC_ASYNC) ||
>  	     (! is_playback && attr == USB_ENDPOINT_SYNC_ADAPTIVE)) &&
>  	    altsd->bNumEndpoints >= 2) {
> +		switch (subs->stream->chip->usb_id) {
> +		case USB_ID(0x0763, 0x2080): /* M-Audio FastTrack Ultra */
> +		case USB_ID(0x0763, 0x2081):
> +			ep = 0x81;
> +			iface = usb_ifnum_to_if(dev, 2);
> +			alts = &iface->altsetting[1];

Better check that the device actually has these descriptors.

> +int snd_usb_substream_capture_trigger(struct snd_pcm_substream *substream, int cmd)
> +{
> +	case SNDRV_PCM_TRIGGER_START:
> +		err = start_endpoints(subs);

The trigger callback should execute very quickly; the initial URB
submission should be handled in the prepare callback.


Regards,
Clemens