ALSA: intelhdmi - sticky stream id and format

We tracked down the first-0.5s-hdmi-audio-samples-lost problem to the
AC_VERB_SET_CHANNEL_STREAMID command. It is suspected that many HDMI
sinks need some time to adapt to the new state.

The workaround is to avoid changing stream id/format whenever possible.
Proposed by David.

Signed-off-by: David Härdeman <david@hardeman.nu>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 26 insertions, 2 deletions

diff --git a/sound/pci/hda/patch_intelhdmi.c b/sound/pci/hda/patch_intelhdmi.c
index abb056fde67..8a1cf9d7e5c 100644
--- a/sound/pci/hda/patch_intelhdmi.c
+++ b/sound/pci/hda/patch_intelhdmi.c
@@ -772,6 +772,31 @@ static void intel_hdmi_unsol_event(struct hda_codec *codec, unsigned int res)
  * Callbacks
  */
 
+static void hdmi_setup_stream(struct hda_codec *codec, hda_nid_t nid,
+                              u32 stream_tag, int format)
+{
+        int tag;
+        int fmt;
+
+        tag = snd_hda_codec_read(codec, nid, 0, AC_VERB_GET_CONV, 0) >> 4;
+        fmt = snd_hda_codec_read(codec, nid, 0, AC_VERB_GET_STREAM_FORMAT, 0);
+
+        snd_printdd("hdmi_setup_stream: "
+                    "NID=0x%x, %sstream=0x%x, %sformat=0x%x\n",
+                    nid,
+                    tag == stream_tag ? "" : "new-",
+                    stream_tag,
+                    fmt == format ? "" : "new-",
+                    format);
+
+        if (tag != stream_tag)
+                snd_hda_codec_write(codec, nid, 0,
+                                    AC_VERB_SET_CHANNEL_STREAMID, stream_tag << 4);
+        if (fmt != format)
+                snd_hda_codec_write(codec, nid, 0,
+                                    AC_VERB_SET_STREAM_FORMAT, format);
+}
+
 static int intel_hdmi_playback_pcm_prepare(struct hda_pcm_stream *hinfo,
                                            struct hda_codec *codec,
                                            unsigned int stream_tag,
@@ -783,7 +808,7 @@ static int intel_hdmi_playback_pcm_prepare(struct hda_pcm_stream *hinfo,
 
         hdmi_setup_audio_infoframe(codec, hinfo->nid, substream);
 
-        snd_hda_codec_setup_stream(codec, hinfo->nid, stream_tag, 0, format);
+        hdmi_setup_stream(codec, hinfo->nid, stream_tag, format);
         return 0;
 }
 
@@ -791,7 +816,6 @@ static int intel_hdmi_playback_pcm_cleanup(struct hda_pcm_stream *hinfo,
                                            struct hda_codec *codec,
                                            struct snd_pcm_substream *substream)
 {
-        snd_hda_codec_cleanup_stream(codec, hinfo->nid);
         return 0;
 }