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Commit d948035a authored by Takashi Iwai's avatar Takashi Iwai Committed by Jaroslav Kysela
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[ALSA] Remove PCM xfer_align sw params 



The xfer_align sw_params parameter has never been used in a sane manner,
and no one understands what this does exactly.  The current
implementation looks also buggy because it allows write of shorter size
than xfer_align.  So, if you do partial writes, the write isn't actually
aligned at all.
Removing this parameter will make some pcm_lib_* code more readable
(and less buggy).

Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
Signed-off-by: default avatarJaroslav Kysela <perex@perex.cz>
parent fa5717f2

Documentation/sound/alsa/DocBook/writing-an-alsa-driver.tmpl

+0 −1
Original line number Diff line number Diff line
@@ -2188,7 +2188,6 @@ struct _snd_pcm_runtime { 
	struct timespec tstamp_mode;	/* mmap timestamp is updated */

  	unsigned int period_step;

	unsigned int sleep_min;		/* min ticks to sleep */

	snd_pcm_uframes_t xfer_align;	/* xfer size need to be a multiple */

	snd_pcm_uframes_t start_threshold;

	snd_pcm_uframes_t stop_threshold;

	snd_pcm_uframes_t silence_threshold; /* Silence filling happens when

include/sound/asound.h

+1 −1
Original line number Diff line number Diff line
@@ -363,7 +363,7 @@ struct snd_pcm_sw_params { 
	unsigned int period_step;

	unsigned int sleep_min;			/* min ticks to sleep */

	snd_pcm_uframes_t avail_min;		/* min avail frames for wakeup */

	snd_pcm_uframes_t xfer_align;		/* xfer size need to be a multiple */

	snd_pcm_uframes_t xfer_align;		/* obsolete: xfer size need to be a multiple */

	snd_pcm_uframes_t start_threshold;	/* min hw_avail frames for automatic start */

	snd_pcm_uframes_t stop_threshold;	/* min avail frames for automatic stop */

	snd_pcm_uframes_t silence_threshold;	/* min distance from noise for silence filling */

include/sound/pcm.h

+0 −1
Original line number Diff line number Diff line
@@ -287,7 +287,6 @@ struct snd_pcm_runtime { 
	int tstamp_mode;		/* mmap timestamp is updated */

  	unsigned int period_step;

	unsigned int sleep_min;		/* min ticks to sleep */

	snd_pcm_uframes_t xfer_align;	/* xfer size need to be a multiple */

	snd_pcm_uframes_t start_threshold;

	snd_pcm_uframes_t stop_threshold;

	snd_pcm_uframes_t silence_threshold; /* Silence filling happens when

sound/core/oss/pcm_oss.c

+0 −1
Original line number Diff line number Diff line
@@ -988,7 +988,6 @@ static int snd_pcm_oss_change_params(struct snd_pcm_substream *substream) 
	sw_params->sleep_min = 0;

	sw_params->avail_min = substream->stream == SNDRV_PCM_STREAM_PLAYBACK ?

		1 : runtime->period_size;

	sw_params->xfer_align = 1;

	if (atomic_read(&substream->mmap_count) ||

	    substream->oss.setup.nosilence) {

		sw_params->silence_threshold = 0;

sound/core/pcm.c

+0 −1
Original line number Diff line number Diff line
@@ -389,7 +389,6 @@ static void snd_pcm_substream_proc_sw_params_read(struct snd_info_entry *entry, 
	snd_iprintf(buffer, "period_step: %u\n", runtime->period_step);

	snd_iprintf(buffer, "sleep_min: %u\n", runtime->sleep_min);

	snd_iprintf(buffer, "avail_min: %lu\n", runtime->control->avail_min);

	snd_iprintf(buffer, "xfer_align: %lu\n", runtime->xfer_align);

	snd_iprintf(buffer, "start_threshold: %lu\n", runtime->start_threshold);

	snd_iprintf(buffer, "stop_threshold: %lu\n", runtime->stop_threshold);

	snd_iprintf(buffer, "silence_threshold: %lu\n", runtime->silence_threshold);