ASoC: OMAP: Set minimum buffer size constraint for McBSP2 in OMAP3

[pandora-kernel.git] / sound / soc / omap / omap-mcbsp.c

diff --git a/sound/soc/omap/omap-mcbsp.c b/sound/soc/omap/omap-mcbsp.c
index d6882be..9c09b94 100644 (file)
--- a/sound/soc/omap/omap-mcbsp.c
+++ b/sound/soc/omap/omap-mcbsp.c
@@ -146,6 +146,17 @@ static int omap_mcbsp_dai_startup(struct snd_pcm_substream *substream,
        struct omap_mcbsp_data *mcbsp_data = to_mcbsp(cpu_dai->private_data);
        int err = 0;
 
+       if (cpu_is_omap343x() && mcbsp_data->bus_id == 1) {
+               /*
+                * McBSP2 in OMAP3 has 1024 * 32-bit internal audio buffer.
+                * Set constraint for minimum buffer size to the same than FIFO
+                * size in order to avoid underruns in playback startup because
+                * HW is keeping the DMA request active until FIFO is filled.
+                */
+               snd_pcm_hw_constraint_minmax(substream->runtime,
+                       SNDRV_PCM_HW_PARAM_BUFFER_BYTES, 4096, UINT_MAX);
+       }
+
        if (!cpu_dai->active)
                err = omap_mcbsp_request(mcbsp_data->bus_id);