ALSA: asihpi: Handle playback drained status better

Use the card drained status reporting for playback,
but allow it to persist for a few timer cycles before
signalling XRUN, to allow card to recover by itself.
Signed-off-by: Eliot Blennerhassett <eblennerhassett@audioscience.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/pci/asihpi/asihpi.c

@@ -165,6 +165,7 @@ struct snd_card_asihpi_pcm {
 	unsigned int pcm_buf_host_rw_ofs; /* Host R/W pos */
 	unsigned int pcm_buf_dma_ofs;	/* DMA R/W offset in buffer */
 	unsigned int pcm_buf_elapsed_dma_ofs;	/* DMA R/W offset in buffer */
+	unsigned int drained_count;
 	struct snd_pcm_substream *substream;
 	u32 h_stream;
 	struct hpi_format format;
@@ -592,6 +593,7 @@ static int snd_card_asihpi_trigger(struct snd_pcm_substream *substream,
 			if (substream->stream != s->stream)
 				continue;
 
+			ds->drained_count = 0;
 			if ((s->stream == SNDRV_PCM_STREAM_PLAYBACK) &&
 				(card->support_mmap)) {
 				/* How do I know how much valid data is present
@@ -771,12 +773,18 @@ static void snd_card_asihpi_timer_function(unsigned long data)
 				    (on_card_bytes < ds->pcm_buf_host_rw_ofs)) {
 					hpi_handle_error(hpi_stream_start(ds->h_stream));
 					snd_printdd("P%d start\n", s->number);
+					ds->drained_count = 0;
 				}
 			} else if (state == HPI_STATE_DRAINED) {
 				snd_printd(KERN_WARNING "P%d drained\n",
 						s->number);
-				/*snd_pcm_stop(s, SNDRV_PCM_STATE_XRUN);
-				continue; */
+				ds->drained_count++;
+				if (ds->drained_count > 2) {
+					snd_pcm_stop(s, SNDRV_PCM_STATE_XRUN);
+					continue;
+				}
+			} else {
+				ds->drained_count = 0;
 			}
 		} else
 			pcm_buf_dma_ofs = bytes_avail + ds->pcm_buf_host_rw_ofs;