[PATCH] ASoC: SOF: ipc4-pcm: Look for best matching hw_config for SSP

[PATCH] ASoC: SOF: ipc4-pcm: Look for best matching hw_config for SSP

[Peter Ujfalusi]

Instead of just looking for a hw_config with matching rate only it sounds
better to try to find the best matching configuration.

If we have multiple hw_configurations with the same rate, but each with
different format for example then we have been picking the first config
with the matching rate, which can be a problem and it wil depend on how
the configs are ordered.

Instead we should be trying to find the best match out of the configs
1. rate + format + channels are matching
2. rate + format are matching
3. rate matching

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>
Reviewed-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
---
 sound/soc/sof/ipc4-pcm.c | 61 ++++++++++++++++++++++++++++++----------
 1 file changed, 46 insertions(+), 15 deletions(-)

diff --git a/sound/soc/sof/ipc4-pcm.c b/sound/soc/sof/ipc4-pcm.c
index 8eee3e1aadf9..a5b365ab1945 100644
--- a/sound/soc/sof/ipc4-pcm.c
+++ b/sound/soc/sof/ipc4-pcm.c
@@ -557,12 +557,15 @@ static int sof_ipc4_pcm_hw_free(struct snd_soc_component *component,
 	return sof_ipc4_trigger_pipelines(component, substream, SOF_IPC4_PIPE_RESET, 0);
 }
 
-static void ipc4_ssp_dai_config_pcm_params_match(struct snd_sof_dev *sdev, const char *link_name,
-						 struct snd_pcm_hw_params *params)
+static int ipc4_ssp_dai_config_pcm_params_match(struct snd_sof_dev *sdev,
+						const char *link_name,
+						struct snd_pcm_hw_params *params)
 {
 	struct snd_sof_dai_link *slink;
 	struct snd_sof_dai *dai;
 	bool dai_link_found = false;
+	int current_config = -1;
+	bool partial_match;
 	int i;
 
 	list_for_each_entry(slink, &sdev->dai_link_list, list) {
@@ -573,19 +576,50 @@ static void ipc4_ssp_dai_config_pcm_params_match(struct snd_sof_dev *sdev, const
 	}
 
 	if (!dai_link_found)
-		return;
+		return 0;
 
+	/*
+	 * Find the first best matching hardware config:
+	 * rate + format + channels are matching
+	 * rate + channel are matching
+	 *
+	 * The copier cannot do rate and/or channel conversion.
+	 */
 	for (i = 0; i < slink->num_hw_configs; i++) {
 		struct snd_soc_tplg_hw_config *hw_config = &slink->hw_configs[i];
 
-		if (params_rate(params) == le32_to_cpu(hw_config->fsync_rate)) {
-			/* set current config for all DAI's with matching name */
-			list_for_each_entry(dai, &sdev->dai_list, list)
-				if (!strcmp(slink->link->name, dai->name))
-					dai->current_config = le32_to_cpu(hw_config->id);
+		if (params_rate(params) == le32_to_cpu(hw_config->fsync_rate) &&
+		    params_width(params) == le32_to_cpu(hw_config->tdm_slot_width) &&
+		    params_channels(params) == le32_to_cpu(hw_config->tdm_slots)) {
+			current_config = le32_to_cpu(hw_config->id);
+			partial_match = false;
+			/* best match found */
 			break;
+		} else if (current_config < 0 &&
+			   params_rate(params) == le32_to_cpu(hw_config->fsync_rate) &&
+			   params_channels(params) == le32_to_cpu(hw_config->tdm_slots)) {
+			current_config = le32_to_cpu(hw_config->id);
+			partial_match = true;
+			/* keep looking for better match */
 		}
 	}
+
+	if (current_config < 0) {
+		dev_err(sdev->dev,
+			"%s: No suitable hw_config found for %s (num_hw_configs: %d)\n",
+			__func__, slink->link->name, slink->num_hw_configs);
+		return -EINVAL;
+	}
+
+	dev_dbg(sdev->dev,
+		"hw_config for %s: %d (num_hw_configs: %d) with %s match\n",
+		slink->link->name, current_config, slink->num_hw_configs,
+		partial_match ? "partial" : "full");
+	list_for_each_entry(dai, &sdev->dai_list, list)
+		if (!strcmp(slink->link->name, dai->name))
+			dai->current_config = current_config;
+
+	return 0;
 }
 
 /*
@@ -728,13 +762,10 @@ static int sof_ipc4_pcm_dai_link_fixup(struct snd_soc_pcm_runtime *rtd,
 		break;
 	}
 
-	switch (ipc4_copier->dai_type) {
-	case SOF_DAI_INTEL_SSP:
-		ipc4_ssp_dai_config_pcm_params_match(sdev, (char *)rtd->dai_link->name, params);
-		break;
-	default:
-		break;
-	}
+	if (ipc4_copier->dai_type == SOF_DAI_INTEL_SSP)
+		return ipc4_ssp_dai_config_pcm_params_match(sdev,
+							    (char *)rtd->dai_link->name,
+							    params);
 
 	return 0;
 }
-- 
2.49.0

Re: [PATCH] ASoC: SOF: ipc4-pcm: Look for best matching hw_config for SSP

[Mark Brown]

On Thu, 19 Jun 2025 13:26:57 +0300, Peter Ujfalusi wrote:
> Instead of just looking for a hw_config with matching rate only it sounds
> better to try to find the best matching configuration.
> 
> If we have multiple hw_configurations with the same rate, but each with
> different format for example then we have been picking the first config
> with the matching rate, which can be a problem and it wil depend on how
> the configs are ordered.
> 
> [...]

Applied to

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

Thanks!

[1/1] ASoC: SOF: ipc4-pcm: Look for best matching hw_config for SSP
      commit: 8a07944a77e962b625c582696497964c393a3489

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