uaol: add UAOL feedback support by serhiy-katsyuba-intel · Pull Request #11265 · thesofproject/sof

serhiy-katsyuba-intel · 2026-10-02T18:24:02Z

This extends UAOL functionality to support audio rate adjustment based on the "desired" clock reported by the USB playback device via the USB feedback endpoint. The firmware calculates drift from this feedback and instructs UAOL hardware to increase or decrease the transfer rate accordingly.

A DSRC (Drift-compensating adaptive Sample Rate Converter) is used when necessary to perform audio resampling and compensate for small dynamic drift.

Depends on Zephyr PR: zephyrproject-rtos/zephyr#121128

*** DO NOT MERGE *** This commit will be swapped with proper one once Zephyr PR is merged. Signed-off-by: Serhiy Katsyuba <serhiy.katsyuba@intel.com>

Copilot

Copilot review overview

🟡 Changes recommended

Error propagation, buffer sizing and format handling, DMA rollback, undefined arithmetic, and dependency pinning must be corrected.

Review effort: Balanced
Findings: 4 · 2 · 2

Open (8)

DSRC lacks validation for unsupported sample formats · New
DSRC buffer is too small for fast-mode copies · New
Allocation failure incorrectly reports success · New
DMA byte count is misused for source-format processing · New
Feedback start failure leaves audio DMA running · New
Negative reconstructed sample is left-shifted undefinedly · New
Public DSRC APIs lack required documentation · New
Unpinned feedback branch makes the manifest nonreproducible · New

What changed in this PR

Adds UAOL USB feedback handling and DSRC-based drift compensation to the SOF DAI path.

Changes:

Adds feedback DMA setup, processing, and UAOL rate adjustment.
Introduces and tests a lightweight DSRC implementation.
Updates the Zephyr dependency for required UAOL support.

File	Description
`west.yml`	Selects a UAOL-enabled Zephyr revision.
`test/ztest/unit/dsrc/testcase.yaml`	Registers DSRC tests.
`test/ztest/unit/dsrc/test_input.txt`	Adds DSRC input data.
`test/ztest/unit/dsrc/test_expected_2.txt`	Adds expected resampling output.
`test/ztest/unit/dsrc/test_dsrc_ztest.c`	Tests DSRC rates and output.
`test/ztest/unit/dsrc/prj.conf`	Configures the test application.
`test/ztest/unit/dsrc/CMakeLists.txt`	Builds the DSRC tests.
`src/ipc/ipc4/dai.c`	Configures and releases feedback DMA.
`src/include/sof/lib/dai-zephyr.h`	Adds UAOL DAI runtime state.
`src/include/sof/audio/intel_uaol.h`	Declares UAOL feedback helpers.
`src/include/sof/audio/dsrc.h`	Defines the DSRC API and state.
`src/audio/intel_uaol.c`	Implements feedback and rate adjustment.
`src/audio/dsrc.c`	Implements drift resampling.
`src/audio/dai-zephyr.c`	Integrates feedback DMA and DSRC processing.
`src/audio/CMakeLists.txt`	Adds DSRC to UAOL builds.

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+	if (dd->ipc_config.type == SOF_DAI_INTEL_UAOL &&
+			dd->ipc_config.direction == SOF_IPC_STREAM_PLAYBACK) {
+		/* resampling might generate 1 extra frame; DSRC only works with 32-bit data */
+		size_t dsrc_buf_size = (dev->frames + 1) * dd->ipc_config.gtw_fmt->channels_count * 4;
+		dd->uaol.dsrc_buf = buffer_alloc_range(&dd->alloc_ctx, dsrc_buf_size,


+		/* resampling might generate 1 extra frame; DSRC only works with 32-bit data */
+		size_t dsrc_buf_size = (dev->frames + 1) * dd->ipc_config.gtw_fmt->channels_count * 4;
+		dd->uaol.dsrc_buf = buffer_alloc_range(&dd->alloc_ctx, dsrc_buf_size,
+						       dsrc_buf_size,
+					       SOF_MEM_FLAG_USER, PLATFORM_DCACHE_ALIGN,
+					       BUFFER_USAGE_NOT_SHARED);


+	if (dd->uaol.feedback_drift > 0) {
+		buffer_stream_invalidate(dd->local_buffer, bytes);
+
+		struct cir_buf_ptr in = { dd->local_buffer->stream.addr,
+			dd->local_buffer->stream.end_addr, dd->local_buffer->stream.r_ptr };
+		assert(dd->uaol.dsrc_buf);
+		struct cir_buf_ptr out = { dd->uaol.dsrc_buf->stream.addr,
+			dd->uaol.dsrc_buf->stream.end_addr, dd->uaol.dsrc_buf->stream.w_ptr };
+		size_t frames = bytes / audio_stream_frame_bytes(&dd->local_buffer->stream);
+
+		size_t added_frames = dsrc_process(&dd->uaol.dsrc, &in, &out, frames);
+		size_t src_added_bytes = added_frames *
+			audio_stream_frame_bytes(&dd->local_buffer->stream);
+
+		comp_update_buffer_consume(dd->local_buffer, bytes);
+		audio_stream_produce(&dd->uaol.dsrc_buf->stream, bytes + src_added_bytes);


This implements a DSRC (Drift-compensating adaptive Sample Rate Converter) for use with the UAOL feedback feature to perform audio resampling and compensate for small dynamic drift. The implementation employs linear interpolation. Signed-off-by: Serhiy Katsyuba <serhiy.katsyuba@intel.com>

This adds unit tests for DSRC using Zephyr's ztest framework. Signed-off-by: Serhiy Katsyuba <serhiy.katsyuba@intel.com>

Make dai_get_properties_safe() non-static and declare it in sof/lib/dai-zephyr.h so that DAI-specific code outside dai-zephyr.c (e.g., intel_uaol.c) can use it. Signed-off-by: Serhiy Katsyuba <serhiy.katsyuba@intel.com>

This extends UAOL functionality to support audio rate adjustment based on the "desired" clock reported by the USB playback device via the USB feedback endpoint. The firmware calculates drift from this feedback and instructs UAOL hardware to increase or decrease the transfer rate accordingly. A DSRC (Drift-compensating adaptive Sample Rate Converter) is used when necessary to perform audio resampling and compensate for small dynamic drift. Signed-off-by: Serhiy Katsyuba <serhiy.katsyuba@intel.com>

intel-sofci · 2026-10-05T15:41:49Z

PR 11265: test results

Run date: 2026-10-05 15:22 UTC

Tested commit: e74ee9139b50cfd7d9b29ec426a881655879be57

lgirdwood

Just minor opens, will mark as DNM until Zephyr part is ready.

lgirdwood · 2026-10-10T09:42:00Z


+static void dai_dma_release_channel(struct dai_data *dd)
+{
+	if (dd->chan_index >= 0) {


does this need to be atomic, i.e. if we have multiple USB streams ?

lgirdwood · 2026-10-10T09:43:39Z

+	}
+
+#if CONFIG_UAOL_INTEL_ADSP
+	if (dd->uaol.fb_chan_idx >= 0) {


it would be good to state via inline comment why we need call certain ops twice for UAOL, i.e. so its understood that its intended.

lgirdwood · 2026-10-10T09:44:56Z

+	 * there is no easy access to "params" there to set up the buffer format.
+	 */
+#ifdef CONFIG_UAOL_INTEL_ADSP
+	/* create DSRC output buffer (if needed) */


btw, do we have the option to plumb in higher performance ASRC instead of DRC ?

[***DNM***] use private Zephyr

db4c9b1

*** DO NOT MERGE *** This commit will be swapped with proper one once Zephyr PR is merged. Signed-off-by: Serhiy Katsyuba <serhiy.katsyuba@intel.com>

Copilot AI balanced review requested due to automatic review settings October 2, 2026 18:24

serhiy-katsyuba-intel requested review from dbaluta, kv2019i, lbetlej, lgirdwood, mmaka1 and plbossart as code owners October 2, 2026 18:24

Copilot started reviewing on behalf of serhiy-katsyuba-intel October 2, 2026 18:25 View session

Copilot AI reviewed Oct 2, 2026

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serhiy-katsyuba-intel added 4 commits October 2, 2026 22:43

test: uaol: add DSRC unit tests

99ce602

This adds unit tests for DSRC using Zephyr's ztest framework. Signed-off-by: Serhiy Katsyuba <serhiy.katsyuba@intel.com>

audio: dai-zephyr: export dai_get_properties_safe()

1de3cbf

Make dai_get_properties_safe() non-static and declare it in sof/lib/dai-zephyr.h so that DAI-specific code outside dai-zephyr.c (e.g., intel_uaol.c) can use it. Signed-off-by: Serhiy Katsyuba <serhiy.katsyuba@intel.com>

serhiy-katsyuba-intel force-pushed the uaol_feedback_0210_2 branch from b186022 to e74ee91 Compare October 2, 2026 20:58

serhiy-katsyuba-intel requested a review from ujfalusi October 3, 2026 16:25

lgirdwood reviewed Oct 10, 2026

View reviewed changes

lgirdwood added the DNM Do Not Merge tag label Oct 10, 2026

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uaol: add UAOL feedback support - #11265

uaol: add UAOL feedback support#11265
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serhiy-katsyuba-intel:uaol_feedback_0210_2

serhiy-katsyuba-intel commented Oct 2, 2026 •

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intel-sofci commented Oct 5, 2026

PR 11265: test results

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serhiy-katsyuba-intel commented Oct 2, 2026 •

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