Since commit 
13882a82ee16 (optimize iso queueing by setting
wake only after the last packet), drivers are required to call
fw_iso_context_queue_flush() after queueing a batch of packets.
The missing call would have an effect only if the controller
queue underruns, but then the DMA would stop completely.
Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
 
                isight->packet_index = -1;
                return;
        }
+       fw_iso_context_queue_flush(isight->context);
 
        if (++index >= QUEUE_LENGTH)
                index = 0;