diff options
Diffstat (limited to 'sound/core/pcm_lib.c')
| -rw-r--r-- | sound/core/pcm_lib.c | 52 |
1 files changed, 42 insertions, 10 deletions
diff --git a/sound/core/pcm_lib.c b/sound/core/pcm_lib.c index 6f73b3c2c205..6e7905749c4a 100644 --- a/sound/core/pcm_lib.c +++ b/sound/core/pcm_lib.c @@ -516,21 +516,38 @@ void snd_pcm_set_ops(struct snd_pcm *pcm, int direction, EXPORT_SYMBOL(snd_pcm_set_ops); /** - * snd_pcm_set_sync - set the PCM sync id + * snd_pcm_set_sync_per_card - set the PCM sync id with card number * @substream: the pcm substream + * @params: modified hardware parameters + * @id: identifier (max 12 bytes) + * @len: identifier length (max 12 bytes) * - * Sets the PCM sync identifier for the card. + * Sets the PCM sync identifier for the card with zero padding. + * + * User space or any user should use this 16-byte identifier for a comparison only + * to check if two IDs are similar or different. Special case is the identifier + * containing only zeros. Interpretation for this combination is - empty (not set). + * The contents of the identifier should not be interpreted in any other way. + * + * The synchronization ID must be unique per clock source (usually one sound card, + * but multiple soundcard may use one PCM word clock source which means that they + * are fully synchronized). + * + * This routine composes this ID using card number in first four bytes and + * 12-byte additional ID. When other ID composition is used (e.g. for multiple + * sound cards), make sure that the composition does not clash with this + * composition scheme. */ -void snd_pcm_set_sync(struct snd_pcm_substream *substream) +void snd_pcm_set_sync_per_card(struct snd_pcm_substream *substream, + struct snd_pcm_hw_params *params, + const unsigned char *id, unsigned int len) { - struct snd_pcm_runtime *runtime = substream->runtime; - - runtime->sync.id32[0] = substream->pcm->card->number; - runtime->sync.id32[1] = -1; - runtime->sync.id32[2] = -1; - runtime->sync.id32[3] = -1; + *(__u32 *)params->sync = cpu_to_le32(substream->pcm->card->number); + len = min(12, len); + memcpy(params->sync + 4, id, len); + memset(params->sync + 4 + len, 0, 12 - len); } -EXPORT_SYMBOL(snd_pcm_set_sync); +EXPORT_SYMBOL_GPL(snd_pcm_set_sync_per_card); /* * Standard ioctl routine @@ -1810,6 +1827,18 @@ static int snd_pcm_lib_ioctl_fifo_size(struct snd_pcm_substream *substream, return 0; } +static int snd_pcm_lib_ioctl_sync_id(struct snd_pcm_substream *substream, + void *arg) +{ + static const unsigned char id[12] = { 0xff, 0xff, 0xff, 0xff, + 0xff, 0xff, 0xff, 0xff, + 0xff, 0xff, 0xff, 0xff }; + + if (substream->runtime->std_sync_id) + snd_pcm_set_sync_per_card(substream, arg, id, sizeof(id)); + return 0; +} + /** * snd_pcm_lib_ioctl - a generic PCM ioctl callback * @substream: the pcm substream instance @@ -1831,6 +1860,8 @@ int snd_pcm_lib_ioctl(struct snd_pcm_substream *substream, return snd_pcm_lib_ioctl_channel_info(substream, arg); case SNDRV_PCM_IOCTL1_FIFO_SIZE: return snd_pcm_lib_ioctl_fifo_size(substream, arg); + case SNDRV_PCM_IOCTL1_SYNC_ID: + return snd_pcm_lib_ioctl_sync_id(substream, arg); } return -ENXIO; } @@ -2556,6 +2587,7 @@ int snd_pcm_add_chmap_ctls(struct snd_pcm *pcm, int stream, struct snd_kcontrol_new knew = { .iface = SNDRV_CTL_ELEM_IFACE_PCM, .access = SNDRV_CTL_ELEM_ACCESS_READ | + SNDRV_CTL_ELEM_ACCESS_VOLATILE | SNDRV_CTL_ELEM_ACCESS_TLV_READ | SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK, .info = pcm_chmap_ctl_info, |