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pcm: ioplug: Use boundary for wrap around

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if requested by the IO plugin

Without this changes an IO plugin is not able to report
that buffer_size frames were read from the buffer.
When the buffer was full this is a valid action and
has not to be handled as an under run.

For example when the hw_ptr will be updated with
hw_ptr += buffer_size
and it is using the buffer_size as wrap around
hw_ptr %= buffer_size
would result in the same value as before the add operation.

Signed-off-by: Timo Wischer <twischer@de.adit-jv.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Timo Wischer 2018-02-23 10:28:51 +01:00 • committed by Takashi Iwai
parent af531606b7
commit 543a9eac5d
2 changed files with 16 additions and 6 deletions
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5
include/pcm_ioplug.h
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@ -65,6 +65,8 @@ typedef snd_pcm_ioplug_callback snd_pcm_ioplug_callback_t;
*/
#define SND_PCM_IOPLUG_FLAG_LISTED (1<<0) /**< list up this PCM */
#define SND_PCM_IOPLUG_FLAG_MONOTONIC (1<<1) /**< monotonic timestamps */
/** hw pointer wrap around at boundary instead of buffer_size */
#define SND_PCM_IOPLUG_FLAG_BOUNDARY_WA (1<<2)
/*
* Protocol version
@ -133,6 +135,9 @@ struct snd_pcm_ioplug_callback {
int (*stop)(snd_pcm_ioplug_t *io);
/**
* get the current DMA position; required, called inside mutex lock
* \return buffer position up to buffer_size or
* when #SND_PCM_IOPLUG_FLAG_BOUNDARY_WA flag is set up to boundary or
* a negative error code for Xrun
*/
snd_pcm_sframes_t (*pointer)(snd_pcm_ioplug_t *io);
/**