Commit 1250932e authored by Jaroslav Kysela's avatar Jaroslav Kysela
Browse files

ALSA: pcm_lib - optimize wake_up() calls for PCM I/O 



As noted by pl bossart <bossart.nospam@gmail.com>, the PCM I/O routines
(snd_pcm_lib_write1, snd_pcm_lib_read1) should block wake_up() calls
until all samples are not processed.

Signed-off-by: default avatarJaroslav Kysela <perex@perex.cz>
parent f240406b

include/sound/pcm.h

+3 −0
Original line number Diff line number Diff line
@@ -311,6 +311,7 @@ struct snd_pcm_runtime { 
	struct snd_pcm_mmap_control *control;



	/* -- locking / scheduling -- */

	unsigned int nowake: 1;		/* no wakeup (data-copy in progress) */

	wait_queue_head_t sleep;

	struct fasync_struct *fasync;
@@ -839,6 +840,8 @@ void snd_pcm_set_sync(struct snd_pcm_substream *substream); 
int snd_pcm_lib_interleave_len(struct snd_pcm_substream *substream);

int snd_pcm_lib_ioctl(struct snd_pcm_substream *substream,

		      unsigned int cmd, void *arg);                      

int snd_pcm_update_state(struct snd_pcm_substream *substream,

			 struct snd_pcm_runtime *runtime);

int snd_pcm_update_hw_ptr(struct snd_pcm_substream *substream);

int snd_pcm_playback_xrun_check(struct snd_pcm_substream *substream);

int snd_pcm_capture_xrun_check(struct snd_pcm_substream *substream);

sound/core/pcm_lib.c

+20 −10
Original line number Diff line number Diff line
@@ -263,7 +263,7 @@ static void xrun_log_show(struct snd_pcm_substream *substream) 


#endif



static int snd_pcm_update_hw_ptr_post(struct snd_pcm_substream *substream,

int snd_pcm_update_state(struct snd_pcm_substream *substream,

			 struct snd_pcm_runtime *runtime)

{

	snd_pcm_uframes_t avail;
@@ -285,7 +285,7 @@ static int snd_pcm_update_hw_ptr_post(struct snd_pcm_substream *substream, 
			return -EPIPE;

		}

	}

	if (avail >= runtime->control->avail_min)

	if (!runtime->nowake && avail >= runtime->control->avail_min)

		wake_up(&runtime->sleep);

	return 0;

}
@@ -441,7 +441,7 @@ static int snd_pcm_update_hw_ptr0(struct snd_pcm_substream *substream, 
	if (runtime->tstamp_mode == SNDRV_PCM_TSTAMP_ENABLE)

		snd_pcm_gettime(runtime, (struct timespec *)&runtime->status->tstamp);



	return snd_pcm_update_hw_ptr_post(substream, runtime);

	return snd_pcm_update_state(substream, runtime);

}



/* CAUTION: call it with irq disabled */
@@ -1792,6 +1792,7 @@ static snd_pcm_sframes_t snd_pcm_lib_write1(struct snd_pcm_substream *substream, 
		goto _end_unlock;

	}



	runtime->nowake = 1;

	while (size > 0) {

		snd_pcm_uframes_t frames, appl_ptr, appl_ofs;

		snd_pcm_uframes_t avail;
@@ -1813,15 +1814,17 @@ static snd_pcm_sframes_t snd_pcm_lib_write1(struct snd_pcm_substream *substream, 
		if (frames > cont)

			frames = cont;

		if (snd_BUG_ON(!frames)) {

			runtime->nowake = 0;

			snd_pcm_stream_unlock_irq(substream);

			return -EINVAL;

		}

		appl_ptr = runtime->control->appl_ptr;

		appl_ofs = appl_ptr % runtime->buffer_size;

		snd_pcm_stream_unlock_irq(substream);

		if ((err = transfer(substream, appl_ofs, data, offset, frames)) < 0)

			goto _end;

		err = transfer(substream, appl_ofs, data, offset, frames);

		snd_pcm_stream_lock_irq(substream);

		if (err < 0)

			goto _end_unlock;

		switch (runtime->status->state) {

		case SNDRV_PCM_STATE_XRUN:

			err = -EPIPE;
@@ -1850,8 +1853,10 @@ static snd_pcm_sframes_t snd_pcm_lib_write1(struct snd_pcm_substream *substream, 
		}

	}

 _end_unlock:

	runtime->nowake = 0;

	if (xfer > 0 && err >= 0)

		snd_pcm_update_state(substream, runtime);

	snd_pcm_stream_unlock_irq(substream);

 _end:

	return xfer > 0 ? (snd_pcm_sframes_t)xfer : err;

}
@@ -2009,6 +2014,7 @@ static snd_pcm_sframes_t snd_pcm_lib_read1(struct snd_pcm_substream *substream, 
		goto _end_unlock;

	}



	runtime->nowake = 1;

	while (size > 0) {

		snd_pcm_uframes_t frames, appl_ptr, appl_ofs;

		snd_pcm_uframes_t avail;
@@ -2037,15 +2043,17 @@ static snd_pcm_sframes_t snd_pcm_lib_read1(struct snd_pcm_substream *substream, 
		if (frames > cont)

			frames = cont;

		if (snd_BUG_ON(!frames)) {

			runtime->nowake = 0;

			snd_pcm_stream_unlock_irq(substream);

			return -EINVAL;

		}

		appl_ptr = runtime->control->appl_ptr;

		appl_ofs = appl_ptr % runtime->buffer_size;

		snd_pcm_stream_unlock_irq(substream);

		if ((err = transfer(substream, appl_ofs, data, offset, frames)) < 0)

			goto _end;

		err = transfer(substream, appl_ofs, data, offset, frames);

		snd_pcm_stream_lock_irq(substream);

		if (err < 0)

			goto _end_unlock;

		switch (runtime->status->state) {

		case SNDRV_PCM_STATE_XRUN:

			err = -EPIPE;
@@ -2068,8 +2076,10 @@ static snd_pcm_sframes_t snd_pcm_lib_read1(struct snd_pcm_substream *substream, 
		xfer += frames;

	}

 _end_unlock:

	runtime->nowake = 0;

	if (xfer > 0 && err >= 0)

		snd_pcm_update_state(substream, runtime);

	snd_pcm_stream_unlock_irq(substream);

 _end:

	return xfer > 0 ? (snd_pcm_sframes_t)xfer : err;

}

sound/core/pcm_native.c

+4 −2
Original line number Diff line number Diff line
@@ -516,6 +516,7 @@ static int snd_pcm_sw_params(struct snd_pcm_substream *substream, 
			     struct snd_pcm_sw_params *params)

{

	struct snd_pcm_runtime *runtime;

	int err;



	if (PCM_RUNTIME_CHECK(substream))

		return -ENXIO;
@@ -540,6 +541,7 @@ static int snd_pcm_sw_params(struct snd_pcm_substream *substream, 
		if (params->silence_threshold > runtime->buffer_size)

			return -EINVAL;

	}

	err = 0;

	snd_pcm_stream_lock_irq(substream);

	runtime->tstamp_mode = params->tstamp_mode;

	runtime->period_step = params->period_step;
@@ -553,10 +555,10 @@ static int snd_pcm_sw_params(struct snd_pcm_substream *substream, 
		if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK &&

		    runtime->silence_size > 0)

			snd_pcm_playback_silence(substream, ULONG_MAX);

		wake_up(&runtime->sleep);

		err = snd_pcm_update_state(substream, runtime);

	}

	snd_pcm_stream_unlock_irq(substream);

	return 0;

	return err;

}



static int snd_pcm_sw_params_user(struct snd_pcm_substream *substream,