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pcm: dsnoop: Added "hw_ptr_alignment" option in configuration for slave pointer alignment

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This change adapt the fix commit 6b058fda9d
("pcm: dmix: Add option to allow alignment of slave pointers")
for dsnoop plugin

Issue is that snd_pcm_wait() goes back to waiting because the hw_ptr
is not period aligned. Therefore snd_pcm_wait() will block for a longer
time as required.

With these rcar driver changes the exact position of the dma is returned.
During snd_pcm_start they read hw_ptr as reference, and this hw_ptr
is now not period aligned, and is a little ahead over the period while it
is read. Therefore when the avail is calculated during snd_pcm_wait(),
it is missing the avail_min by a few frames.

An additional option hw_ptr_alignment is provided to dsnoop configuration,
to allow the user to configure the slave application and hw pointer
alignment at startup

Signed-off-by: Vanitha Channaiah <vanitha.channaiah@in.bosch.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Vanitha Channaiah 2019-05-15 11:56:34 +05:30 • committed by Takashi Iwai
parent 7265e603bf
commit 3ab7980047
4 changed files with 33 additions and 2 deletions
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2
src/pcm/pcm_dmix.c
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@ -562,6 +562,7 @@ static int snd_pcm_dmix_reset(snd_pcm_t *pcm)
snd_pcm_direct_t *dmix = pcm->private_data;
dmix->hw_ptr %= pcm->period_size;
dmix->appl_ptr = dmix->last_appl_ptr = dmix->hw_ptr;
dmix->slave_appl_ptr = dmix->slave_hw_ptr = *dmix->spcm->hw.ptr;
snd_pcm_direct_reset_slave_ptr(pcm, dmix);
return 0;
}
@ -571,6 +572,7 @@ static int snd_pcm_dmix_start_timer(snd_pcm_t *pcm, snd_pcm_direct_t *dmix)
int err;
snd_pcm_hwsync(dmix->spcm);
dmix->slave_appl_ptr = dmix->slave_hw_ptr = *dmix->spcm->hw.ptr;
snd_pcm_direct_reset_slave_ptr(pcm, dmix);
err = snd_timer_start(dmix->timer);
if (err < 0)