[PATCH v3] ASoC: soc-generic-dmaengine: Handle DMA channel request failures correctly

[PATCH v3] ASoC: soc-generic-dmaengine: Handle DMA channel request failures correctly

[phucduc.bui]

From: bui duc phuc <phucduc.bui@gmail.com>

Currently any dma_request_chan() failure other than -EPROBE_DEFER is
silently ignored, since a missing channel is expected for devices that
only support one DMA direction.

Improve the handling of these failures by:
- reporting failures when a configured DMA channel cannot be requested;
- failing probe if neither playback nor capture obtains a DMA channel,
  since the PCM device would be unusable.

Devices that legitimately support only one DMA direction continue to
work as before.

Signed-off-by: bui duc phuc <phucduc.bui@gmail.com>
---

Changes in v3:
 - Drop has_legacy_config, since config->chan_names[] only provides the
   requested channel name and does not indicate legacy DMA mapping.
Changes in v2:
 - Update the commit message and title.
 - Refine DMA channel request failure handling to match the
   dma_request_chan() implementation.

 sound/soc/soc-generic-dmaengine-pcm.c | 28 +++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/sound/soc/soc-generic-dmaengine-pcm.c b/sound/soc/soc-generic-dmaengine-pcm.c
index 467426d2b5e4..98ba9a836936 100644
--- a/sound/soc/soc-generic-dmaengine-pcm.c
+++ b/sound/soc/soc-generic-dmaengine-pcm.c
@@ -3,6 +3,7 @@
 //  Copyright (C) 2013, Analog Devices Inc.
 //	Author: Lars-Peter Clausen <lars@metafoo.de>
 
+#include <linux/acpi.h>
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/dmaengine.h>
@@ -395,6 +396,27 @@ static int dmaengine_pcm_request_chan_of(struct dmaengine_pcm *pcm,
 			 */
 			if (PTR_ERR(chan) == -EPROBE_DEFER)
 				return -EPROBE_DEFER;
+
+			bool has_fw_node = dev->of_node || is_acpi_device_node(dev->fwnode);
+			bool name_exists_in_fw = false;
+
+			if (has_fw_node)
+				name_exists_in_fw = device_property_match_string(dev,
+										 "dma-names",
+										 name) >= 0;
+
+			if (has_fw_node && name_exists_in_fw)
+				dev_warn(dev, "DTS/ACPI DMA channel '%s' request failed (%ld)\n",
+					 name, PTR_ERR(chan));
+
+			if (has_fw_node && !name_exists_in_fw)
+				dev_warn(dev, "DTS/ACPI name '%s' not found, legacy failed (%ld)\n",
+					 name, PTR_ERR(chan));
+
+			if (!has_fw_node)
+				dev_warn(dev, "Legacy DMA channel '%s' request failed (%ld)\n",
+					 name, PTR_ERR(chan));
+
 			pcm->chan[i] = NULL;
 		} else {
 			pcm->chan[i] = chan;
@@ -406,6 +428,12 @@ static int dmaengine_pcm_request_chan_of(struct dmaengine_pcm *pcm,
 	if (pcm->flags & SND_DMAENGINE_PCM_FLAG_HALF_DUPLEX)
 		pcm->chan[1] = pcm->chan[0];
 
+	if (!pcm->chan[0] &&
+	    !pcm->chan[1]) {
+		dev_err(dev, "no DMA channel found for either playback or capture\n");
+		return -ENODEV;
+	}
+
 	return 0;
 }
 
-- 
2.43.0

Re: [PATCH v3] ASoC: soc-generic-dmaengine: Handle DMA channel request failures correctly

[Mark Brown]

On Mon, 20 Jul 2026 13:41:31 +0700, phucduc.bui@gmail.com wrote:
> ASoC: soc-generic-dmaengine: Handle DMA channel request failures correctly

Applied to

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git for-7.3

Thanks!

[1/1] ASoC: soc-generic-dmaengine: Handle DMA channel request failures correctly
      https://git.kernel.org/broonie/sound/c/9167f260477b

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark