[ALSA] at73c213: Add constraints for periods value

The interrupt handler always provide runtime->period_size data, so it
works correctly only if buffer_size was a multiple of period_size.

This patch fixes periodic click noise.

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/spi/at73c213.c b/sound/spi/at73c213.c
index aa57115..09802e8 100644 (file)
--- a/sound/spi/at73c213.c
+++ b/sound/spi/at73c213.c
@@ -210,7 +210,13 @@ static int snd_at73c213_pcm_open(struct snd_pcm_substream *substream)
 {
        struct snd_at73c213 *chip = snd_pcm_substream_chip(substream);
        struct snd_pcm_runtime *runtime = substream->runtime;
+       int err;
 
+       /* ensure buffer_size is a multiple of period_size */
+       err = snd_pcm_hw_constraint_integer(runtime,
+                                       SNDRV_PCM_HW_PARAM_PERIODS);
+       if (err < 0)
+               return err;
        snd_at73c213_playback_hw.rate_min = chip->bitrate;
        snd_at73c213_playback_hw.rate_max = chip->bitrate;
        runtime->hw = snd_at73c213_playback_hw;