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| author | Mark Brown <broonie@kernel.org> | 2020-10-08 17:11:05 +0100 |
|---|---|---|
| committer | Mark Brown <broonie@kernel.org> | 2020-10-09 15:11:20 +0100 |
| commit | 86f29c7442ac4ba5fe19fc2ada457f76c0080dd6 (patch) | |
| tree | b4ccc96962338b19b77b220e014879feb7f9bc89 /sound | |
| parent | b899e4fd7a331065d01ca14809c9e55f113f7d05 (diff) | |
| download | lwn-86f29c7442ac4ba5fe19fc2ada457f76c0080dd6.tar.gz lwn-86f29c7442ac4ba5fe19fc2ada457f76c0080dd6.zip | |
ASoC: dmaengine: Document support for TX only or RX only streams
We intentionally do not return an error if we get a permanent failure
from dma_request_chan() in order to support systems which have TX only
or RX only channels. Add a comment documenting this.
Reported-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Link: https://lore.kernel.org/r/20201008161105.21804-1-broonie@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'sound')
| -rw-r--r-- | sound/soc/soc-generic-dmaengine-pcm.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/sound/soc/soc-generic-dmaengine-pcm.c b/sound/soc/soc-generic-dmaengine-pcm.c index fb95c1464e66..9ef80a48707e 100644 --- a/sound/soc/soc-generic-dmaengine-pcm.c +++ b/sound/soc/soc-generic-dmaengine-pcm.c @@ -386,6 +386,11 @@ static int dmaengine_pcm_request_chan_of(struct dmaengine_pcm *pcm, name = config->chan_names[i]; chan = dma_request_chan(dev, name); if (IS_ERR(chan)) { + /* + * Only report probe deferral errors, channels + * might not be present for devices that + * support only TX or only RX. + */ if (PTR_ERR(chan) == -EPROBE_DEFER) return -EPROBE_DEFER; pcm->chan[i] = NULL; |