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Thu, 8 Oct 2020 16:11:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1602173468; bh=odcKIcS2rgXtVOQJF+X7d4lRwwnaPshBaElk+qxy4ic=; h=From:To:Cc:Subject:Date:From; b=sG6qsaJ0AqzsCcOBMmbYk8s1Q4+TikkEN46droiZNmAAjzUch8NzlRPVIGsOtvXKs oea4yZSD3pTGgvDuTmDDMD+uioX4MYHNDRlz8mpI2X9GxEkXS3byibw6ZMKb+DX02e 0yx2yQZm5pQFzuIAiN+vqaDS3WwqJZr8tSsmlACE= From: Mark Brown To: Lars-Peter Clausen Subject: [PATCH] ASoC: dmaengine: Document support for TX only or RX only streams Date: Thu, 8 Oct 2020 17:11:05 +0100 Message-Id: <20201008161105.21804-1-broonie@kernel.org> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 X-Patch-Hashes: v=1; h=sha256; g=162830429688f269a2838f01494536323d46febd; i=VXVW0rYh+ve73oT0wQBc/womMjipEaviTdprhgXTq3o=; m=GbDHjudT1QLZ/QEHMmXmBgQ81c4UJHbv2/wsGpRgmHM=; p=vItuo2g+nIOV9Gy+EpdpJsEea8XtAIgbjc/ZmqwQGTM= X-Patch-Sig: m=pgp; i=broonie@kernel.org; s=0xC3F436CA30F5D8EB; b=iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAl9/OKUACgkQJNaLcl1Uh9CSNAf/W8y Oco2Lhfz59RDIikV1KcQU+Wanj0MqAI66crblRuzrb/Y3+IGefCvCAnS4/ucUje4+Cfr63L7JqG/1 WisyI38EjoohrtM6zpaKb/k8aP7l+t+kT7iJ3RqNxoyA0usKK9X5qOHvMv9tIptyrsYbVcm2DkjGV MLmpuu5EXiOU4mXNc6RayKASKt+TtMTYkWyR4Y2IOCTcvNj2GZvcNZSqRApQPJBiezZU8ns7PW87N NXdBvjleLdaKKOX8+VjcwTpCEhzvxGRcF/oGZe+epaHZimtTadhZYeOcpQqAYczkY9BTmYhss76gI KyqNLtvyJEl3cg0HHGGwIBsjqiWqQYg== Cc: alsa-devel@alsa-project.org, Stephen Warren , Andy Shevchenko , Liam Girdwood , Pierre-Louis Bossart , Mark Brown , Michael Wei Hong Sit X-BeenThere: alsa-devel@alsa-project.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: "Alsa-devel mailing list for ALSA developers - http://www.alsa-project.org" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: alsa-devel-bounces@alsa-project.org Sender: "Alsa-devel" 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 Signed-off-by: Mark Brown --- 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;