ASoC: SOF: add SOF_DBG_CHECK_SDW_PERIPHERAL debug flag by bardliao · Pull Request #5741 · thesofproject/linux

bardliao · 2026-04-20T13:39:34Z

If the flag is set, the driver waits for and verifies the presence of SoundWire peripherals listed in the ACPI table. This prevents the system from probing non-existent (ghost) SoundWire devices.

Copilot

Pull request overview

Adds a new SOF debug flag to optionally wait for SoundWire enumeration and filter out “ghost” peripherals listed in ACPI, avoiding machine-driver selection based on non-existent devices.

Changes:

Introduces SOF_DBG_CHECK_SDW_PERIPHERAL debug flag.
Adds an optional enumeration wait/verification step in hda_sdw_machine_select() before generating ACPI link/ADR structures.
Adds a local enumeration timeout constant.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 5 comments.

File	Description
sound/soc/sof/sof-priv.h	Adds a new SOF debug flag definition controlling SoundWire peripheral presence checks.
sound/soc/sof/intel/hda.c	Implements the optional wait-for-enumeration logic during SoundWire default machine selection.

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Copilot · 2026-04-20T13:46:20Z

 	for (i = 0; i < peripherals->num_peripherals; i++) {
+		slave = peripherals->array[i];
+
+		/* Check is the peripheral is present */


Typo/grammar in the new comment: "Check is the peripheral is present" should be "Check if the peripheral is present" (and keep SoundWire capitalization consistent).

Suggested change

/* Check is the peripheral is present */

/* Check if the SoundWire peripheral is present */

Copilot · 2026-04-20T13:46:20Z

 							 * DSPLESS_MODE is not set.
 							 * No audio functionality when enabled.
 							 */
+#define SOF_DBG_CHECK_SDW_PERIPHERAL		BIT(17) /* Check is Soundwire peripherals are


Grammar/capitalization in the new flag description: "Check is Soundwire peripherals are" should be "Check if SoundWire peripherals are".

Suggested change

#define SOF_DBG_CHECK_SDW_PERIPHERAL BIT(17) /* Check is Soundwire peripherals are

#define SOF_DBG_CHECK_SDW_PERIPHERAL BIT(17) /* Check if SoundWire peripherals are

Copilot · 2026-04-20T13:46:21Z

+		/* Check is the peripheral is present */
+		if (sof_debug_check_flag(SOF_DBG_CHECK_SDW_PERIPHERAL) && !slave->dev_num_sticky) {
+			/* Wait for the peripheral to enumerate */
+			time = wait_for_completion_timeout(&slave->enumeration_complete,
+							   msecs_to_jiffies(ENUMERATION_TIMEOUT));
+			if (!time) {
+				dev_warn(&slave->dev, "SoundWire peripheral is not present\n");
+				continue;
+			}


The new continue when a SoundWire peripheral fails to enumerate can leave a link entry with num_adr == 0 while link_mask still includes that link. Several SoundWire helper paths iterate mach_params->links until num_adr == 0 (null-terminated contract), so an empty entry can prematurely terminate parsing and ignore later valid links/devices. Consider building a present_link_mask first (after the optional wait), allocating links based on that mask (+1 for a terminating entry), and only emitting link entries for links that have at least one present peripheral (and update mach->mach_params.link_mask accordingly).

@copilot apply changes based on this feedback

Copilot · 2026-04-20T13:46:21Z

 	return adr_dev;
 }

+#define ENUMERATION_TIMEOUT 3000


ENUMERATION_TIMEOUT is a very generic macro name and doesn’t document the unit. Rename it to something scoped (e.g. SOF_SDW_ENUMERATION_TIMEOUT_MS) and/or add a _MS suffix so it’s clear this value is in milliseconds.

Suggested change

#define ENUMERATION_TIMEOUT 3000

#define SOF_SDW_ENUMERATION_TIMEOUT_MS 3000

Copilot

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

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Copilot · 2026-04-21T01:44:07Z

 	return adr_dev;
 }

+#define ENUMERATION_TIMEOUT 3000


ENUMERATION_TIMEOUT is a very generic macro name and the units aren’t obvious at the definition site. Since it’s passed to msecs_to_jiffies(), consider renaming to something like HDA_SDW_ENUMERATION_TIMEOUT_MS (or adding a short comment) to make the units and scope clear and reduce the risk of collisions.

Suggested change

#define ENUMERATION_TIMEOUT 3000

#define ENUMERATION_TIMEOUT 3000 /* milliseconds, used with msecs_to_jiffies() for HDA SoundWire enumeration */

Copilot

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

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Copilot · 2026-04-22T10:01:58Z

 		return NULL;

+	/*
+	 * Recalculate the link_mask as a link will be empty if all peripherals on the link are 


There is trailing whitespace at the end of this comment line; please remove it to avoid checkpatch warnings.

Suggested change

* Recalculate the link_mask as a link will be empty if all peripherals on the link are

* Recalculate the link_mask as a link will be empty if all peripherals on the link are

Copilot · 2026-04-22T10:01:58Z

+#define SOF_DBG_CHECK_SDW_PERIPHERAL		BIT(17) /* Check if SoundWire peripherals are
+							 * present while selecting machine driver
+							 */


This new macro definition line is very long due to the inline block comment; consider moving the comment above the #define (or shortening it) to better match kernel style and avoid checkpatch line-length warnings.

Suggested change

#define SOF_DBG_CHECK_SDW_PERIPHERAL BIT(17) /* Check if SoundWire peripherals are

* present while selecting machine driver

*/

/* Check if SoundWire peripherals are present while selecting machine driver */

#define SOF_DBG_CHECK_SDW_PERIPHERAL BIT(17)

This aligned to other DBG flag defines.

Copilot · 2026-04-22T10:01:59Z

 	links = devm_kcalloc(sdev->dev, link_num, sizeof(*links), GFP_KERNEL);
 	if (!links)
 		return NULL;

+	/*


mach_params->links is expected to be terminated by an entry with num_adr == 0 (e.g. asoc_sdw_count_sdw_endpoints()/asoc_sdw_parse_sdw_endpoints() iterate for (adr_link = mach_params->links; adr_link->num_adr; adr_link++)). Here links is allocated with exactly link_num entries, so when all links have at least one enumerated peripheral there is no terminating element and the iteration can read past the end of the allocation. Allocate link_num + 1 entries (zero-initialized) and keep the last one as the terminator (or recompute link_num from the final mask and still add a terminator).

Thanks for pointing it out. I will submit another PR to address it.

If the flag is set, the driver waits for and verifies the presence of SoundWire peripherals listed in the ACPI table. This prevents the system from probing non-existent (ghost) SoundWire devices. Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>

bardliao requested review from Copilot, naveen-manohar and ujfalusi April 20, 2026 13:39

bardliao requested review from lyakh and ranj063 as code owners April 20, 2026 13:39

Copilot started reviewing on behalf of bardliao April 20, 2026 13:40 View session

Copilot AI reviewed Apr 20, 2026

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bardliao force-pushed the for-sdw-ghost branch from 1910553 to 9f41376 Compare April 21, 2026 01:36

Copilot AI review requested due to automatic review settings April 21, 2026 01:38

bardliao force-pushed the for-sdw-ghost branch from 9f41376 to a93739b Compare April 21, 2026 01:38

Copilot started reviewing on behalf of bardliao April 21, 2026 01:39 View session

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bardliao force-pushed the for-sdw-ghost branch 2 times, most recently from c2f293d to 21ea49d Compare April 22, 2026 09:55

Copilot AI review requested due to automatic review settings April 22, 2026 09:55

Copilot started reviewing on behalf of bardliao April 22, 2026 09:56 View session

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bardliao mentioned this pull request Apr 22, 2026

No audio on ASUS Zenbook S14 UX5406AA (Panther Lake): sof_sdw fails to create DAI links for cs35l56 #5721

Open

bardliao force-pushed the for-sdw-ghost branch from 21ea49d to 24e3063 Compare April 22, 2026 11:23

	/* Check is the peripheral is present */
	/* Check if the SoundWire peripheral is present */

	#define SOF_DBG_CHECK_SDW_PERIPHERAL BIT(17) /* Check is Soundwire peripherals are
	#define SOF_DBG_CHECK_SDW_PERIPHERAL BIT(17) /* Check if SoundWire peripherals are

	#define ENUMERATION_TIMEOUT 3000
	#define SOF_SDW_ENUMERATION_TIMEOUT_MS 3000

	#define ENUMERATION_TIMEOUT 3000
	#define ENUMERATION_TIMEOUT 3000 /* milliseconds, used with msecs_to_jiffies() for HDA SoundWire enumeration */

	* Recalculate the link_mask as a link will be empty if all peripherals on the link are
	* Recalculate the link_mask as a link will be empty if all peripherals on the link are

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