Unverified Commit 9aff2e8d authored by Sheetal's avatar Sheetal Committed by Mark Brown
Browse files

ASoC: soc-pcm: Fix hw_params() and DAPM widget sequence 



Issue:
 When multiple audio streams share a common BE DAI, the BE DAI
 widget can be powered up before its hardware parameters are configured.
 This incorrect sequence leads to intermittent pcm_write errors.

 For example, the below Tegra use-case throws an error:
  aplay(2 streams) -> AMX(mux) -> ADX(demux) -> arecord(2 streams),
  here, 'AMX TX' and 'ADX RX' are common BE DAIs.

For above usecase when failure happens below sequence is observed:
 aplay(1) FE open()
  - BE DAI callbacks added to the list
  - BE DAI state = SND_SOC_DPCM_STATE_OPEN
 aplay(2) FE open()
  - BE DAI callbacks are not added to the list as the state is
    already SND_SOC_DPCM_STATE_OPEN during aplay(1) FE open().
 aplay(2) FE hw_params()
  - BE DAI hw_params() callback ignored
 aplay(2) FE prepare()
  - Widget is powered ON without BE DAI hw_params() call
 aplay(1) FE hw_params()
  - BE DAI hw_params() is now called

Fix:
 Add BE DAIs in the list if its state is either SND_SOC_DPCM_STATE_OPEN
 or SND_SOC_DPCM_STATE_HW_PARAMS as well.

It ensures the widget is powered ON after BE DAI hw_params() callback.

Fixes: 0c25db3f ("ASoC: soc-pcm: Don't reconnect an already active BE")
Signed-off-by: default avatarSheetal <sheetal@nvidia.com>
Link: https://patch.msgid.link/20250404105953.2784819-1-sheetal@nvidia.com


Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent a9a69c3b

sound/soc/soc-pcm.c

+4 −1
Original line number Diff line number Diff line
@@ -1584,10 +1584,13 @@ int dpcm_add_paths(struct snd_soc_pcm_runtime *fe, int stream, 
		/*

		 * Filter for systems with 'component_chaining' enabled.

		 * This helps to avoid unnecessary re-configuration of an

		 * already active BE on such systems.

		 * already active BE on such systems and ensures the BE DAI

		 * widget is powered ON after hw_params() BE DAI callback.

		 */

		if (fe->card->component_chaining &&

		    (be->dpcm[stream].state != SND_SOC_DPCM_STATE_NEW) &&

		    (be->dpcm[stream].state != SND_SOC_DPCM_STATE_OPEN) &&

		    (be->dpcm[stream].state != SND_SOC_DPCM_STATE_HW_PARAMS) &&

		    (be->dpcm[stream].state != SND_SOC_DPCM_STATE_CLOSE))

			continue;