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Commit ef18bede authored by Wu Fengguang's avatar Wu Fengguang Committed by Takashi Iwai
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ALSA: hda - HDMI sticky stream tag support 



When we run the following commands in turn (with
CONFIG_SND_HDA_POWER_SAVE_DEFAULT=0),

	speaker-test -Dhw:0,3 -c2 -twav  # HDMI
	speaker-test -Dhw:0,0 -c2 -twav  # Analog

The second command will produce sound in the analog lineout _as well as_
HDMI sink. The root cause is, device 0 "reuses" the same stream tag that
was used by device 3, and the "intelhdmi - sticky stream id" patch leaves
the HDMI codec in a functional state. So the HDMI codec happily accepts
the audio samples which reuse its stream tag.

The proposed solution is to remember the last device each azx_dev was
assigned to, and prefer to
1) reuse the azx_dev (and hence the stream tag) the HDMI codec last used
2) or assign a never-used azx_dev for HDMI

With this patch and the above two speaker-test commands,
HDMI codec will use stream tag 8 and Analog codec will use 5.

The stream tag used by HDMI codec won't be reused by others, as long
as we don't run out of the 4 playback azx_dev's. The legacy Analog
codec will continue to use stream tag 5 because its device id is 0
(this is a bit tricky).

Signed-off-by: default avatarWu Fengguang <fengguang.wu@intel.com>
Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 6b7b2849

sound/pci/hda/hda_intel.c

+15 −6
Original line number Diff line number Diff line
@@ -356,6 +356,7 @@ struct azx_dev { 
					 */

	unsigned char stream_tag;	/* assigned stream */

	unsigned char index;		/* stream index */

	int device;			/* last device number assigned to */



	unsigned int opened :1;

	unsigned int running :1;
@@ -1441,10 +1442,13 @@ static int __devinit azx_codec_configure(struct azx *chip) 
 */



/* assign a stream for the PCM */

static inline struct azx_dev *azx_assign_device(struct azx *chip, int stream)

static inline struct azx_dev *

azx_assign_device(struct azx *chip, struct snd_pcm_substream *substream)

{

	int dev, i, nums;

	if (stream == SNDRV_PCM_STREAM_PLAYBACK) {

	struct azx_dev *res = NULL;



	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {

		dev = chip->playback_index_offset;

		nums = chip->playback_streams;

	} else {
@@ -1453,10 +1457,15 @@ static inline struct azx_dev *azx_assign_device(struct azx *chip, int stream) 
	}

	for (i = 0; i < nums; i++, dev++)

		if (!chip->azx_dev[dev].opened) {

			chip->azx_dev[dev].opened = 1;

			return &chip->azx_dev[dev];

			res = &chip->azx_dev[dev];

			if (res->device == substream->pcm->device)

				break;

		}

	if (res) {

		res->opened = 1;

		res->device = substream->pcm->device;

	}

	return NULL;

	return res;

}



/* release the assigned stream */
@@ -1505,7 +1514,7 @@ static int azx_pcm_open(struct snd_pcm_substream *substream) 
	int err;



	mutex_lock(&chip->open_mutex);

	azx_dev = azx_assign_device(chip, substream->stream);

	azx_dev = azx_assign_device(chip, substream);

	if (azx_dev == NULL) {

		mutex_unlock(&chip->open_mutex);

		return -EBUSY;