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ASoC: SOF: PCM: add period_elapsed work to fix race condition in interrupt context 

The IPC implementation in SOF requires sending IPCs serially: we should
not send a new IPC command to the firmware before we get an ACK (or time
out) from firmware, and the IRQ processing is complete.

snd_pcm_period_elapsed() can be called in interrupt context before
IRQ_HANDLED is returned. When the PCM is done draining, a STOP
IPC will then be sent, which breaks the expectation that IPCs are
handled serially and leads to IPC timeouts.

This patch adds a workqueue to defer the call to snd_pcm_elapsed() after
the IRQ is handled.

Signed-off-by: Keyon Jie <yang.jie@linux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Keyon Jie 2019-04-30 18:09:25 -05:00 committed by Mark Brown
parent b0056fda7c
commit e2803e610a
No known key found for this signature in database
GPG Key ID: 24D68B725D5487D0
2 changed files with 50 additions and 0 deletions
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48
sound/soc/sof/pcm.c
View File

@ -52,6 +52,48 @@ static int sof_pcm_dsp_params(struct snd_sof_pcm *spcm, struct snd_pcm_substream
return ret;
}
/*
* sof pcm period elapse work
*/
static void sof_pcm_period_elapsed_work(struct work_struct *work)
{
struct snd_sof_pcm_stream *sps =
container_of(work, struct snd_sof_pcm_stream,
period_elapsed_work);
snd_pcm_period_elapsed(sps->substream);
}
/*
* sof pcm period elapse, this could be called at irq thread context.
*/
void snd_sof_pcm_period_elapsed(struct snd_pcm_substream *substream)
{
struct snd_soc_pcm_runtime *rtd = substream->private_data;
struct snd_soc_component *component =
snd_soc_rtdcom_lookup(rtd, DRV_NAME);
struct snd_sof_dev *sdev = snd_soc_component_get_drvdata(component);
struct snd_sof_pcm *spcm;
spcm = snd_sof_find_spcm_dai(sdev, rtd);
if (!spcm) {
dev_err(sdev->dev,
"error: period elapsed for unknown stream!\n");
return;
}
/*
* snd_pcm_period_elapsed() can be called in interrupt context
* before IRQ_HANDLED is returned. Inside snd_pcm_period_elapsed(),
* when the PCM is done draining or xrun happened, a STOP IPC will
* then be sent and this IPC will hit IPC timeout.
* To avoid sending IPC before the previous IPC is handled, we
* schedule delayed work here to call the snd_pcm_period_elapsed().
*/
schedule_work(&spcm->stream[substream->stream].period_elapsed_work);
}
EXPORT_SYMBOL(snd_sof_pcm_period_elapsed);
/* this may get called several times by oss emulation */
static int sof_pcm_hw_params(struct snd_pcm_substream *substream,
struct snd_pcm_hw_params *params)
@ -169,6 +211,9 @@ static int sof_pcm_hw_params(struct snd_pcm_substream *substream,
/* save pcm hw_params */
memcpy(&spcm->params[substream->stream], params, sizeof(*params));
INIT_WORK(&spcm->stream[substream->stream].period_elapsed_work,
sof_pcm_period_elapsed_work);
return ret;
}
@ -203,6 +248,9 @@ static int sof_pcm_hw_free(struct snd_pcm_substream *substream)
sizeof(stream), &reply, sizeof(reply));
snd_pcm_lib_free_pages(substream);
cancel_work_sync(&spcm->stream[substream->stream].period_elapsed_work);
return ret;
}

2
sound/soc/sof/sof-priv.h
View File

@ -274,6 +274,7 @@ struct snd_sof_pcm_stream {
struct snd_dma_buffer page_table;
struct sof_ipc_stream_posn posn;
struct snd_pcm_substream *substream;
struct work_struct period_elapsed_work;
};
/* ALSA SOF PCM device */
@ -495,6 +496,7 @@ struct snd_sof_pcm *snd_sof_find_spcm_comp(struct snd_sof_dev *sdev,
int *direction);
struct snd_sof_pcm *snd_sof_find_spcm_pcm_id(struct snd_sof_dev *sdev,
unsigned int pcm_id);
void snd_sof_pcm_period_elapsed(struct snd_pcm_substream *substream);
/*
* Stream IPC