Commit ed3da3d9 authored by Takashi Iwai's avatar Takashi Iwai
Browse files

ALSA: Rewrite hw_ptr updaters 



Clean up and improve snd_pcm_update_hw_ptr*() functions.

snd_pcm_update_hw_ptr() tries to detect the unexpected hwptr jumps
more strictly to avoid the position mess-up, which often results in
the bad quality I/O with pulseaudio.

The hw-ptr skip error messages are printed when xrun proc is set to
non-zero.

Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 2450cf51

sound/core/pcm_lib.c

+83 −45
Original line number Diff line number Diff line
@@ -125,19 +125,27 @@ void snd_pcm_playback_silence(struct snd_pcm_substream *substream, snd_pcm_ufram 
	}

}



#ifdef CONFIG_SND_PCM_XRUN_DEBUG

#define xrun_debug(substream)	((substream)->pstr->xrun_debug)

#else

#define xrun_debug(substream)	0

#endif



#define dump_stack_on_xrun(substream) do {	\

		if (xrun_debug(substream) > 1)	\

			dump_stack();		\

	} while (0)



static void xrun(struct snd_pcm_substream *substream)

{

	snd_pcm_stop(substream, SNDRV_PCM_STATE_XRUN);

#ifdef CONFIG_SND_PCM_XRUN_DEBUG

	if (substream->pstr->xrun_debug) {

	if (xrun_debug(substream)) {

		snd_printd(KERN_DEBUG "XRUN: pcmC%dD%d%c\n",

			   substream->pcm->card->number,

			   substream->pcm->device,

			   substream->stream ? 'c' : 'p');

		if (substream->pstr->xrun_debug > 1)

			dump_stack();

		dump_stack_on_xrun(substream);

	}

#endif

}



static inline snd_pcm_uframes_t snd_pcm_update_hw_ptr_pos(struct snd_pcm_substream *substream,
@@ -182,11 +190,21 @@ static inline int snd_pcm_update_hw_ptr_post(struct snd_pcm_substream *substream 
	return 0;

}



#define hw_ptr_error(substream, fmt, args...)				\

	do {								\

		if (xrun_debug(substream)) {				\

			if (printk_ratelimit()) {			\

				snd_printd("hda_codec: " fmt, ##args);	\

			}						\

			dump_stack_on_xrun(substream);			\

		}							\

	} while (0)



static inline int snd_pcm_update_hw_ptr_interrupt(struct snd_pcm_substream *substream)

{

	struct snd_pcm_runtime *runtime = substream->runtime;

	snd_pcm_uframes_t pos;

	snd_pcm_uframes_t new_hw_ptr, hw_ptr_interrupt;

	snd_pcm_uframes_t new_hw_ptr, hw_ptr_interrupt, hw_base;

	snd_pcm_sframes_t delta;



	pos = snd_pcm_update_hw_ptr_pos(substream, runtime);
@@ -194,36 +212,47 @@ static inline int snd_pcm_update_hw_ptr_interrupt(struct snd_pcm_substream *subs 
		xrun(substream);

		return -EPIPE;

	}

	if (runtime->period_size == runtime->buffer_size)

		goto __next_buf;

	new_hw_ptr = runtime->hw_ptr_base + pos;

	hw_base = runtime->hw_ptr_base;

	new_hw_ptr = hw_base + pos;

	hw_ptr_interrupt = runtime->hw_ptr_interrupt + runtime->period_size;



	delta = hw_ptr_interrupt - new_hw_ptr;

	if (delta > 0) {

		if ((snd_pcm_uframes_t)delta < runtime->buffer_size / 2) {

#ifdef CONFIG_SND_PCM_XRUN_DEBUG

			if (runtime->periods > 1 && substream->pstr->xrun_debug) {

				snd_printd(KERN_ERR "Unexpected hw_pointer value [1] (stream = %i, delta: -%ld, max jitter = %ld): wrong interrupt acknowledge?\n", substream->stream, (long) delta, runtime->buffer_size / 2);

				if (substream->pstr->xrun_debug > 1)

					dump_stack();

			}

#endif

			return 0;

		}

	      __next_buf:

		runtime->hw_ptr_base += runtime->buffer_size;

		if (runtime->hw_ptr_base == runtime->boundary)

			runtime->hw_ptr_base = 0;

		new_hw_ptr = runtime->hw_ptr_base + pos;

	delta = new_hw_ptr - hw_ptr_interrupt;

	if (hw_ptr_interrupt == runtime->boundary)

		hw_ptr_interrupt = 0;

	if (delta < 0) {

		delta += runtime->buffer_size;

		if (delta < 0) {

			hw_ptr_error(substream, 

				     "Unexpected hw_pointer value "

				     "(stream=%i, pos=%ld, intr_ptr=%ld)\n",

				     substream->stream, (long)pos,

				     (long)hw_ptr_interrupt);

			/* rebase to interrupt position */

			hw_base = new_hw_ptr = hw_ptr_interrupt;

			delta = 0;

		} else {

			hw_base += runtime->buffer_size;

			if (hw_base == runtime->boundary)

				hw_base = 0;

			new_hw_ptr = hw_base + pos;

		}

	}

	if (delta > runtime->period_size) {

		hw_ptr_error(substream,

			     "Lost interrupts? "

			     "(stream=%i, delta=%ld, intr_ptr=%ld)\n",

			     substream->stream, (long)delta,

			     (long)hw_ptr_interrupt);

		/* rebase hw_ptr_interrupt */

		hw_ptr_interrupt =

			new_hw_ptr - new_hw_ptr % runtime->period_size;

	}



	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK &&

	    runtime->silence_size > 0)

		snd_pcm_playback_silence(substream, new_hw_ptr);



	runtime->hw_ptr_base = hw_base;

	runtime->status->hw_ptr = new_hw_ptr;

	runtime->hw_ptr_interrupt = new_hw_ptr - new_hw_ptr % runtime->period_size;

	runtime->hw_ptr_interrupt = hw_ptr_interrupt;



	return snd_pcm_update_hw_ptr_post(substream, runtime);

}
@@ -233,7 +262,7 @@ int snd_pcm_update_hw_ptr(struct snd_pcm_substream *substream) 
{

	struct snd_pcm_runtime *runtime = substream->runtime;

	snd_pcm_uframes_t pos;

	snd_pcm_uframes_t old_hw_ptr, new_hw_ptr;

	snd_pcm_uframes_t old_hw_ptr, new_hw_ptr, hw_base;

	snd_pcm_sframes_t delta;



	old_hw_ptr = runtime->status->hw_ptr;
@@ -242,29 +271,38 @@ int snd_pcm_update_hw_ptr(struct snd_pcm_substream *substream) 
		xrun(substream);

		return -EPIPE;

	}

	new_hw_ptr = runtime->hw_ptr_base + pos;



	delta = old_hw_ptr - new_hw_ptr;

	if (delta > 0) {

		if ((snd_pcm_uframes_t)delta < runtime->buffer_size / 2) {

#ifdef CONFIG_SND_PCM_XRUN_DEBUG

			if (runtime->periods > 2 && substream->pstr->xrun_debug) {

				snd_printd(KERN_ERR "Unexpected hw_pointer value [2] (stream = %i, delta: -%ld, max jitter = %ld): wrong interrupt acknowledge?\n", substream->stream, (long) delta, runtime->buffer_size / 2);

				if (substream->pstr->xrun_debug > 1)

					dump_stack();

			}

#endif

	hw_base = runtime->hw_ptr_base;

	new_hw_ptr = hw_base + pos;



	delta = new_hw_ptr - old_hw_ptr;

	if (delta < 0) {

		delta += runtime->buffer_size;

		if (delta < 0) {

			hw_ptr_error(substream, 

				     "Unexpected hw_pointer value [2] "

				     "(stream=%i, pos=%ld, old_ptr=%ld)\n",

				     substream->stream, (long)pos,

				     (long)old_hw_ptr);

			return 0;

		}

		runtime->hw_ptr_base += runtime->buffer_size;

		if (runtime->hw_ptr_base == runtime->boundary)

			runtime->hw_ptr_base = 0;

		new_hw_ptr = runtime->hw_ptr_base + pos;

		hw_base += runtime->buffer_size;

		if (hw_base == runtime->boundary)

			hw_base = 0;

		new_hw_ptr = hw_base + pos;

	}

	if (delta > runtime->period_size && runtime->periods > 1) {

		hw_ptr_error(substream,

			     "hw_ptr skipping! "

			     "(pos=%ld, delta=%ld, period=%ld)\n",

			     (long)pos, (long)delta,

			     (long)runtime->period_size);

		return 0;

	}

	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK &&

	    runtime->silence_size > 0)

		snd_pcm_playback_silence(substream, new_hw_ptr);



	runtime->hw_ptr_base = hw_base;

	runtime->status->hw_ptr = new_hw_ptr;



	return snd_pcm_update_hw_ptr_post(substream, runtime);

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