linux-kernel - [PATCH] ALSA: pcm_dmaengine: Don't synchronize DMA channel when DMA is paused

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Message-Id: <1721198693-27636-1-git-send-email-shengjiu.wang@nxp.com>
Date: Wed, 17 Jul 2024 14:44:53 +0800
From: Shengjiu Wang <shengjiu.wang@....com>
To: lars@...afoo.de,
	perex@...ex.cz,
	tiwai@...e.com,
	broonie@...nel.org,
	linux-sound@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	alsa-devel@...a-project.org,
	shengjiu.wang@...il.com
Subject: [PATCH] ALSA: pcm_dmaengine: Don't synchronize DMA channel when DMA is paused

When suspended, the DMA channel may enter PAUSE state if dmaengine_pause()
is supported by DMA.
At this state, dmaengine_synchronize() should not be called, otherwise
the DMA channel can't be resumed successfully.

Fixes: e8343410ddf0 ("ALSA: dmaengine: Synchronize dma channel after drop()")
Signed-off-by: Shengjiu Wang <shengjiu.wang@....com>
---
 sound/core/pcm_dmaengine.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/sound/core/pcm_dmaengine.c b/sound/core/pcm_dmaengine.c
index b54336d4bffc..b134a51b3fd5 100644
--- a/sound/core/pcm_dmaengine.c
+++ b/sound/core/pcm_dmaengine.c
@@ -352,8 +352,12 @@ EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_open_request_chan);
 int snd_dmaengine_pcm_sync_stop(struct snd_pcm_substream *substream)
 {
 	struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
+	struct dma_tx_state state;
+	enum dma_status status;
 
-	dmaengine_synchronize(prtd->dma_chan);
+	status = dmaengine_tx_status(prtd->dma_chan, prtd->cookie, &state);
+	if (status != DMA_PAUSED)
+		dmaengine_synchronize(prtd->dma_chan);
 
 	return 0;
 }
-- 
2.34.1