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ALSA: dice: Support for non SYT-Match sampling clock source mode

Forráskód böngészése 
This commit allows this driver to handle devices with non SYT-Match
sampling clock source.

When sampling clock source is SYT-Match mode, devices handle
'presentation timestamp' in received packets and generates sampling clock
according to the information. In this case, driver is synchronization master
and must transfer correct value in SYT field of each packets in outgoing
stream, then the outgoing stream is a master stream.

On the other hand, non SYT-Match mode, devices do this. So drivers must pick
up the value in SYT field of incoming packets and use the value for outgoing
stream. Currently firewire-lib module achieve this work.

Furthermore, without SYT-Match and internal clock source, the sampling rate
should be fixed for the other devices connected to the handled device. This
commit add a restriction of sampling rate at this situation.

With these implementations, this driver has no need to set clock source.
This commit remove set function.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Acked-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Takashi Sakamoto
2014-12-09 00:10:37 +09:00
committed by Takashi Iwai
szülő 9a02843cae
commit 8fc01fc067
4 fájl változott, egészen pontosan 58 új sor hozzáadva és 19 régi sor törölve
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35
sound/firewire/dice/dice-pcm.c
Fájl megtekintése

@@ -140,6 +140,8 @@ end:
static int pcm_open(struct snd_pcm_substream *substream)
{
struct snd_dice *dice = substream->private_data;
unsigned int source, rate;
bool internal;
int err;
err = snd_dice_stream_lock_try(dice);
@@ -149,6 +151,39 @@ static int pcm_open(struct snd_pcm_substream *substream)
err = init_hw_info(dice, substream);
if (err < 0)
goto err_locked;
err = snd_dice_transaction_get_clock_source(dice, &source);
if (err < 0)
goto err_locked;
switch (source) {
case CLOCK_SOURCE_AES1:
case CLOCK_SOURCE_AES2:
case CLOCK_SOURCE_AES3:
case CLOCK_SOURCE_AES4:
case CLOCK_SOURCE_AES_ANY:
case CLOCK_SOURCE_ADAT:
case CLOCK_SOURCE_TDIF:
case CLOCK_SOURCE_WC:
internal = false;
break;
default:
internal = true;
break;
}
/*
* When source of clock is not internal, available sampling rate is
* limited at current sampling rate.
*/
if (!internal) {
err = snd_dice_transaction_get_rate(dice, &rate);
if (err < 0)
goto err_locked;
substream->runtime->hw.rate_min = rate;
substream->runtime->hw.rate_max = rate;
}
snd_pcm_set_sync(substream);
end:
return err;
err_locked: