1 Nov
2011
1 Nov
'11
9:57 p.m.
Daniel Mack wrote:
+++ b/sound/usb/card.h +struct snd_usb_endpoint {
- struct snd_usb_endpoint *sync_slave;
In theory, there could be more than one slave.
+struct snd_usb_endpoint *snd_usb_add_endpoint(struct snd_usb_audio *chip, ...
- /* select the alt setting once so the endpoints become valid */
- snd_printk("%s() calling usb_set_interface()\n", __func__);
- usb_set_interface(ep->chip->dev, ep->iface, ep->alt_idx);
This needs error handling.
+void snd_usb_endpoint_activate(struct snd_usb_endpoint *ep) +{
usb_set_interface(ep->chip->dev, ep->iface, ep->alt_idx);
This too.
+void snd_usb_handle_sync_urb(struct snd_usb_endpoint *ep, +{
for (i = 0; i < in_ctx->packets; i++) {if (urb->iso_frame_desc[i].status == 0)out_ctx->packet_size[i] =urb->iso_frame_desc[i].actual_length / ep->stride;elseout_ctx->packet_size[i] = 0;
When there is any error in any received packet (status != 0), we do not know how many frames to send. Sending zero frames is certain to be wrong and will break synchronization between the two streams.
As far as I can see, the only way to handle such errors is to stop the stream(s) and the PCM device(s).
Regards, Clemens