X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=sound%2Fsoc%2Fomap%2Fomap-pcm.c;h=b411eb460d02b61fdb32a33e6920ca78da5bda64;hb=d3ef3adfa;hp=5e023ba088203f3447ea97ac58428f3776149e43;hpb=3a6c2f8305acbad93fb5c527abb1872f365caddf;p=pandora-kernel.git

diff --git a/sound/soc/omap/omap-pcm.c b/sound/soc/omap/omap-pcm.c
index 5e023ba08820..b411eb460d02 100644
--- a/sound/soc/omap/omap-pcm.c
+++ b/sound/soc/omap/omap-pcm.c
@@ -97,7 +97,7 @@ static int omap_pcm_hw_params(struct snd_pcm_substream *substream,
 	prtd->dma_data = dma_data;
 	err = omap_request_dma(dma_data->dma_req, dma_data->name,
 			       omap_pcm_dma_irq, substream, &prtd->dma_ch);
-	if (!cpu_is_omap1510()) {
+	if (!err & !cpu_is_omap1510()) {
 		/*
 		 * Link channel with itself so DMA doesn't need any
 		 * reprogramming while looping the buffer
@@ -147,12 +147,14 @@ static int omap_pcm_prepare(struct snd_pcm_substream *substream)
 		dma_params.src_or_dst_synch	= OMAP_DMA_DST_SYNC;
 		dma_params.src_start		= runtime->dma_addr;
 		dma_params.dst_start		= dma_data->port_addr;
+		dma_params.dst_port		= OMAP_DMA_PORT_MPUI;
 	} else {
 		dma_params.src_amode		= OMAP_DMA_AMODE_CONSTANT;
 		dma_params.dst_amode		= OMAP_DMA_AMODE_POST_INC;
 		dma_params.src_or_dst_synch	= OMAP_DMA_SRC_SYNC;
 		dma_params.src_start		= dma_data->port_addr;
 		dma_params.dst_start		= runtime->dma_addr;
+		dma_params.src_port		= OMAP_DMA_PORT_MPUI;
 	}
 	/*
 	 * Set DMA transfer frame size equal to ALSA period size and frame
@@ -166,6 +168,31 @@ static int omap_pcm_prepare(struct snd_pcm_substream *substream)
 
 	omap_enable_dma_irq(prtd->dma_ch, OMAP_DMA_FRAME_IRQ);
 
+	/*
+	 * To handle realtime streaming sources properly, we need to be sure
+	 * we have at least 2 periods of size larger than FIFO in the buffer
+	 * to start playing without underflowing. This is because DMA is always
+	 * ahead of playback by amount close to FIFO size and needs to have
+	 * next period ready when previous one finishes transfering to FIFO.
+	 */
+	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK &&
+	    runtime->periods > 1) {
+		struct snd_soc_pcm_runtime *rtd = substream->private_data;
+		int *mcbsp_bus_id = rtd->dai->cpu_dai->private_data;
+		int fifo_samples = (*mcbsp_bus_id == 1) ? 1024 : 256;
+		int period_samples, period_frames;
+		
+		period_samples = bytes_to_samples(runtime,
+				snd_pcm_lib_period_bytes(substream));
+		if (period_samples < fifo_samples + runtime->channels)
+			period_samples = fifo_samples + runtime->channels;
+		period_frames = bytes_to_frames(runtime,
+				samples_to_bytes(runtime, period_samples)) * 2;
+
+		if (runtime->start_threshold < period_frames)
+			runtime->start_threshold = period_frames;
+	}
+
 	return 0;
 }