[PATCH 6.6 14/16] ALSA: pcm_dmaengine: Dont synchronize DMA channel when DMA is paused

Greg Kroah-Hartman
2024-07-25T14:45:21Z

From: Shengjiu Wang <shengjiu.wang@nxp.com>

commit 88e98af9f4b5b0d60c1fe7f7f2701b5467691e75 upstream.

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@nxp.com>
Cc: <stable@vger.kernel.org>
Link: https://patch.msgid.link/1721198693-27636-1-git-send-email-shengjiu.wang@nxp.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
sound/core/pcm_dmaengine.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

--- a/sound/core/pcm_dmaengine.c
+++ b/sound/core/pcm_dmaengine.c
@@ -352,8 +352,12 @@ EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_open
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;
}