diff options
| author | Liam Girdwood <lrg@ti.com> | 2011-07-24 15:59:44 -0400 |
|---|---|---|
| committer | Paolo Pisati <paolo.pisati@canonical.com> | 2012-08-17 04:18:25 -0400 |
| commit | e9965c2a5d98e0d698afe45394b1c77ecc0c99ad (patch) | |
| tree | 3cf2e7919ebfc75ca84a452442a7ec8cf3715309 /sound/core/pcm_lib.c | |
| parent | ad578b9dd93624c073edc24bf5185cd8a90c748d (diff) | |
Subject: [PATCH 075/104] ALSA: pcm - add support for hostless audio
Allow some PCM devices to be hostless, i.e. there is no PCM data transferred
to or from the host CPU. This can be used to minimise power on systems since
the CPU can idle/sleep during the PCM device operation (e.g. a phone call
where the DAI is between a MODEM and DSP)
TODO: cleanup, look at adding a read/write blocker.
Singed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
Diffstat (limited to 'sound/core/pcm_lib.c')
| -rw-r--r-- | sound/core/pcm_lib.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/sound/core/pcm_lib.c b/sound/core/pcm_lib.c index 33884426a64..cd69b38622b 100644 --- a/sound/core/pcm_lib.c +++ b/sound/core/pcm_lib.c | |||
| @@ -1961,6 +1961,9 @@ static int pcm_sanity_check(struct snd_pcm_substream *substream) | |||
| 1961 | struct snd_pcm_runtime *runtime; | 1961 | struct snd_pcm_runtime *runtime; |
| 1962 | if (PCM_RUNTIME_CHECK(substream)) | 1962 | if (PCM_RUNTIME_CHECK(substream)) |
| 1963 | return -ENXIO; | 1963 | return -ENXIO; |
| 1964 | /* TODO: consider and -EINVAL here */ | ||
| 1965 | if (substream->hw_no_buffer) | ||
| 1966 | snd_printd("%s: warning this PCM is host less\n", __func__); | ||
| 1964 | runtime = substream->runtime; | 1967 | runtime = substream->runtime; |
| 1965 | if (snd_BUG_ON(!substream->ops->copy && !runtime->dma_area)) | 1968 | if (snd_BUG_ON(!substream->ops->copy && !runtime->dma_area)) |
| 1966 | return -EINVAL; | 1969 | return -EINVAL; |