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ALSA: only read/clear user-requested nperiods before snd_pcm_start

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This should fix excessive latency with the RayDay that
has a fixed buffersize of 16384 samples.
This commit is contained in:
Robin Gareus 2020-05-01 23:11:18 +02:00
parent b258ad792e
commit 2326fb1638
Signed by: rgareus
GPG Key ID: A090BCE02CF57F04
2 changed files with 5 additions and 4 deletions
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8
libs/backends/alsa/zita-alsa-pcmi.cc
View File

@ -53,6 +53,7 @@ Alsa_pcmi::Alsa_pcmi (
: _fsamp (fsamp)
, _fsize (fsize)
, _play_nfrag (play_nfrag)
, _real_nfrag (play_nfrag)
, _capt_nfrag (capt_nfrag)
, _debug (debug)
, _state (-1)
@ -367,7 +368,7 @@ void Alsa_pcmi::printinfo (void)
fprintf (stdout, "\n nchan : %d\n", _play_nchan);
fprintf (stdout, " fsamp : %d\n", _fsamp);
fprintf (stdout, " fsize : %ld\n", _fsize);
fprintf (stdout, " nfrag : %d\n", _play_nfrag);
fprintf (stdout, " nfrag : %d\n", _real_nfrag);
fprintf (stdout, " format : %s\n", snd_pcm_format_name (_play_format));
}
else fprintf (stdout, " not enabled\n");
@ -484,10 +485,9 @@ void Alsa_pcmi::initialise (const char *play_name, const char *capt_name, const
_state = -4;
return;
}
if (snd_pcm_hw_params_get_periods (_play_hwpar, &nfrag, &dir) || (nfrag != _play_nfrag) || dir)
if (snd_pcm_hw_params_get_periods (_play_hwpar, &_real_nfrag, &dir) || (_real_nfrag != _play_nfrag) || dir)
{
if (_debug & DEBUG_INIT) fprintf (stderr, "Alsa_pcmi warning: requested %u periods for playback, using %u.\n", _play_nfrag, nfrag);
_play_nfrag = nfrag; // this is later used during pcm_start
if (_debug & DEBUG_INIT) fprintf (stderr, "Alsa_pcmi warning: requested %u periods for playback, using %u.\n", _play_nfrag, _real_nfrag);
}
snd_pcm_hw_params_get_format (_play_hwpar, &_play_format);

1
libs/backends/alsa/zita-alsa-pcmi.h
View File

@ -154,6 +154,7 @@ private:
unsigned int _fsamp;
snd_pcm_uframes_t _fsize;
unsigned int _play_nfrag;
unsigned int _real_nfrag;
unsigned int _capt_nfrag;
unsigned int _debug;
int _state;