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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
Download patch file Download diff file Expand all files Collapse all files

5
include/pcm_ioplug.h
View file

@ -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);
/**

17
src/pcm/pcm_ioplug.c
View file

@ -42,7 +42,7 @@ const char *_snd_module_pcm_ioplug = "";
typedef struct snd_pcm_ioplug_priv {
snd_pcm_ioplug_t *data;
struct snd_ext_parm params[SND_PCM_IOPLUG_HW_PARAMS];
unsigned int last_hw;
snd_pcm_uframes_t last_hw;
snd_pcm_uframes_t avail_max;
snd_htimestamp_t trigger_tstamp;
} ioplug_priv_t;
@ -56,13 +56,18 @@ static void snd_pcm_ioplug_hw_ptr_update(snd_pcm_t *pcm)
hw = io->data->callback->pointer(io->data);
if (hw >= 0) {
unsigned int delta;
if ((unsigned int)hw >= io->last_hw)
snd_pcm_uframes_t delta;
if ((snd_pcm_uframes_t)hw >= io->last_hw)
delta = hw - io->last_hw;
else
delta = pcm->buffer_size + hw - io->last_hw;
else {
const snd_pcm_uframes_t wrap_point =
(io->data->flags & SND_PCM_IOPLUG_FLAG_BOUNDARY_WA) ?
pcm->boundary : pcm->buffer_size;
delta = wrap_point + hw - io->last_hw;
}
snd_pcm_mmap_hw_forward(io->data->pcm, delta);
io->last_hw = hw;
io->last_hw = (snd_pcm_uframes_t)hw;
} else
io->data->state = SNDRV_PCM_STATE_XRUN;
}