linux-kernel - [PATCH 1/9] ASoC: qcom: q6apm-dai: set flags to reflect correct operation of appl

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Message-ID: <20251015131740.340258-2-srinivas.kandagatla@oss.qualcomm.com>
Date: Wed, 15 Oct 2025 14:17:31 +0100
From: Srinivas Kandagatla <srinivas.kandagatla@....qualcomm.com>
To: broonie@...nel.org
Cc: perex@...ex.cz, tiwai@...e.com, srini@...nel.org, alexey.klimov@...aro.org,
        linux-sound@...r.kernel.org, m.facchin@...uino.cc,
        linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        Srinivas Kandagatla <srinivas.kandagatla@....qualcomm.com>,
        Stable@...r.kernel.org
Subject: [PATCH 1/9] ASoC: qcom: q6apm-dai: set flags to reflect correct operation of appl_ptr

Driver does not expect the appl_ptr to move backward and requires
explict sync. Make sure that the userspace does not do appl_ptr rewinds
by specifying the correct flags in pcm_info.

Without this patch, the result could be a forever loop as current logic assumes
that appl_ptr can only move forward.

Fixes: 3d4a4411aa8b ("ASoC: q6apm-dai: schedule all available frames to avoid dsp under-runs")
Cc: <Stable@...r.kernel.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@....qualcomm.com>
---
 sound/soc/qcom/qdsp6/q6apm-dai.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/sound/soc/qcom/qdsp6/q6apm-dai.c b/sound/soc/qcom/qdsp6/q6apm-dai.c
index 4ecaff45c518..786ab3222515 100644
--- a/sound/soc/qcom/qdsp6/q6apm-dai.c
+++ b/sound/soc/qcom/qdsp6/q6apm-dai.c
@@ -86,6 +86,7 @@ static const struct snd_pcm_hardware q6apm_dai_hardware_capture = {
 	.info =                 (SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_BLOCK_TRANSFER |
 				 SNDRV_PCM_INFO_MMAP_VALID | SNDRV_PCM_INFO_INTERLEAVED |
 				 SNDRV_PCM_INFO_PAUSE | SNDRV_PCM_INFO_RESUME |
+				 SNDRV_PCM_INFO_NO_REWINDS | SNDRV_PCM_INFO_SYNC_APPLPTR |
 				 SNDRV_PCM_INFO_BATCH),
 	.formats =              (SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S24_LE),
 	.rates =                SNDRV_PCM_RATE_8000_48000,
@@ -105,6 +106,7 @@ static const struct snd_pcm_hardware q6apm_dai_hardware_playback = {
 	.info =                 (SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_BLOCK_TRANSFER |
 				 SNDRV_PCM_INFO_MMAP_VALID | SNDRV_PCM_INFO_INTERLEAVED |
 				 SNDRV_PCM_INFO_PAUSE | SNDRV_PCM_INFO_RESUME |
+				 SNDRV_PCM_INFO_NO_REWINDS | SNDRV_PCM_INFO_SYNC_APPLPTR |
 				 SNDRV_PCM_INFO_BATCH),
 	.formats =              (SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S24_LE),
 	.rates =                SNDRV_PCM_RATE_8000_192000,
-- 
2.51.0