ALSA: hda - Suppress the odd number of channels for HDMI

It looks like that HDMI codecs don't support the odd number of channels
although HD-audio spec doesn't have the restriction.  Add the
hw_constraint to limit to only the even number of channels.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 3 insertions, 0 deletions

diff --git a/sound/pci/hda/patch_hdmi.c b/sound/pci/hda/patch_hdmi.c
index f29b97b5de8f..2d288793ceb3 100644
--- a/sound/pci/hda/patch_hdmi.c
+++ b/sound/pci/hda/patch_hdmi.c
@@ -1238,6 +1238,9 @@ static int simple_playback_pcm_open(struct hda_pcm_stream *hinfo,
                 snd_pcm_hw_constraint_list(substream->runtime, 0,
                                 SNDRV_PCM_HW_PARAM_CHANNELS,
                                 hw_constraints_channels);
+        } else {
+                snd_pcm_hw_constraint_step(substream->runtime, 0,
+                                           SNDRV_PCM_HW_PARAM_CHANNELS, 2);
         }
 
         return snd_hda_multi_out_dig_open(codec, &spec->multiout);