ASoC: SOF: pcm: harden PCM STOP sequence

The old STOP sequence is: 1. stop DMA 2. send STOP ipc
If delay happen before the steps 1 and 2, the DMA buffer will be empty in
short time and cause pipeline xrun then stop the pipeline.
Then the step 2 ipc stop will return error as pipeline is already stopped.

Suggested change to avoid the issue is to switch the order of steps 1 and 2
for the stop sequence.

Signed-off-by: Pan Xiuli <xiuli.pan@linux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20190927200538.660-7-pierre-louis.bossart@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/sound/soc/sof/pcm.c b/sound/soc/sof/pcm.c
index fa7769dd825c42b480f0f2cb658d762d7a3f1293..2b876d4974476bd359d4f530cabfeb92776b3164 100644 (file)
--- a/sound/soc/sof/pcm.c
+++ b/sound/soc/sof/pcm.c
@@ -323,6 +323,7 @@ static int sof_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
        struct sof_ipc_stream stream;
        struct sof_ipc_reply reply;
        bool reset_hw_params = false;
+       bool ipc_first = false;
        int ret;
 
        /* nothing to do for BE */
@@ -343,6 +344,7 @@ static int sof_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
        switch (cmd) {
        case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
                stream.hdr.cmd |= SOF_IPC_STREAM_TRIG_PAUSE;
+               ipc_first = true;
                break;
        case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
                stream.hdr.cmd |= SOF_IPC_STREAM_TRIG_RELEASE;
@@ -363,6 +365,7 @@ static int sof_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
        case SNDRV_PCM_TRIGGER_SUSPEND:
        case SNDRV_PCM_TRIGGER_STOP:
                stream.hdr.cmd |= SOF_IPC_STREAM_TRIG_STOP;
+               ipc_first = true;
                reset_hw_params = true;
                break;
        default:
@@ -370,12 +373,22 @@ static int sof_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
                return -EINVAL;
        }
 
-       snd_sof_pcm_platform_trigger(sdev, substream, cmd);
+       /*
+        * DMA and IPC sequence is different for start and stop. Need to send
+        * STOP IPC before stop DMA
+        */
+       if (!ipc_first)
+               snd_sof_pcm_platform_trigger(sdev, substream, cmd);
 
        /* send IPC to the DSP */
        ret = sof_ipc_tx_message(sdev->ipc, stream.hdr.cmd, &stream,
                                 sizeof(stream), &reply, sizeof(reply));
 
+       /* need to STOP DMA even if STOP IPC failed */
+       if (ipc_first)
+               snd_sof_pcm_platform_trigger(sdev, substream, cmd);
+
+       /* free PCM if reset_hw_params is set and the STOP IPC is successful */
        if (!ret && reset_hw_params)
                ret = sof_pcm_dsp_pcm_free(substream, sdev, spcm);