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@xxxxxxxxx>
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
---
sound/soc/soc-generic-dmaengine-pcm.c | 5 +++++
1 file changed, 5 insertions(+)
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;
--
2.20.1
