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author | Takashi Sakamoto <o-takashi@sakamocchi.jp> | 2014-04-25 13:44:52 (GMT) |
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committer | Takashi Iwai <tiwai@suse.de> | 2014-05-26 12:21:46 (GMT) |
commit | 7b2d99fa6b127707cf0d78feedbb3613aed4d576 (patch) | |
tree | 5dbee1997b68e276446643ac1f7885928337cf3d /sound/firewire/speakers.c | |
parent | 10550bea44a8d7cec8a503c8f91fb6014e7849e9 (diff) | |
download | linux-7b2d99fa6b127707cf0d78feedbb3613aed4d576.tar.xz |
ALSA: firewire-lib/dice/speakers: Add common PCM constraints for AMDTP streams
This commit adds common PCM constraints according to current firewire-lib
implementation.
1.Maximum width for each sample is limited by 24.
AM824 in IEC 61883-6 can deliver 24bit data.
2. Minimum time for period is 5msec.
Apply the old value. For shorter latency, further works are needed.
3. In blocking mode, frames per period/buffer is aligned to 32.
Each packet can include some frames depending on its sampling rate. In
blocking mode, the number equals to SYT_INTERVAL. Currently firewire-lib
can schedule snd_pcm_period_elapsed() for each packet. So, for accurate
PCM interrupt, the number of frames per period/buffer should be aligned
to SYT_INTERVAL.
Currently firewire-lib is lack of better rules to achieve this. So LCM of
each value of SYT_INTERVALs (=32) is applied. This can be improved for
further work.
[Fixed the compile error due to the missing "&" by tiwai]
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/firewire/speakers.c')
-rw-r--r-- | sound/firewire/speakers.c | 8 |
1 files changed, 1 insertions, 7 deletions
diff --git a/sound/firewire/speakers.c b/sound/firewire/speakers.c index c07e7cd..58e7ab0 100644 --- a/sound/firewire/speakers.c +++ b/sound/firewire/speakers.c @@ -167,13 +167,7 @@ static int fwspk_open(struct snd_pcm_substream *substream) if (err < 0) return err; - err = snd_pcm_hw_constraint_minmax(runtime, - SNDRV_PCM_HW_PARAM_PERIOD_TIME, - 5000, UINT_MAX); - if (err < 0) - return err; - - err = snd_pcm_hw_constraint_msbits(runtime, 0, 32, 24); + err = amdtp_stream_add_pcm_hw_constraints(&fwspk->stream, runtime); if (err < 0) return err; |