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livetrax/libs/ardouralsautil/deviceparams.cc
Robin Gareus 0fe3cba8b1
Fix ALSA available buffersize detection:
buffer-size = periods * period-size

Previously, buffersize was used for period-size.

This fixes an issue with a dedicated .asoundrc configuring a specific
period-size or buffer-size that has to be exact.
Ardour's device configuration failed in this case.

This has not been an issues since most hardware devices offer a wide
range: 8 < period-size < 262144 ; 16 < buffer-size < 524288.
Only a subset of which (32 .8192) is allowed by Ardour.
2019-07-24 16:40:32 +02:00

143 lines
4.2 KiB
C++

/*
* Copyright (C) 2015 Robin Gareus <robin@gareus.org>
* Copyright (C) 2013 Paul Davis
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <alsa/asoundlib.h>
#include "pbd/convert.h"
#include "ardouralsautil/deviceinfo.h"
using namespace std;
int
ARDOUR::get_alsa_device_parameters (const char* device_name, const bool play, ALSADeviceInfo *nfo)
{
snd_pcm_t *pcm;
snd_pcm_hw_params_t *hw_params;
std::string errmsg;
int err;
nfo->valid = false;
unsigned long min_psiz, max_psiz;
unsigned long min_bufz, max_bufz;
unsigned int min_nper, max_nper;
err = snd_pcm_open (&pcm, device_name,
play ? SND_PCM_STREAM_PLAYBACK : SND_PCM_STREAM_CAPTURE,
SND_PCM_NONBLOCK);
if (err < 0) {
fprintf (stderr, "ALSA: Cannot open device '%s': %s\n", device_name, snd_strerror (err));
return 1;
}
snd_pcm_hw_params_alloca (&hw_params);
err = snd_pcm_hw_params_any (pcm, hw_params);
if (err < 0) {
errmsg = "Cannot get hardware parameters";
goto error_out;
}
err = snd_pcm_hw_params_get_channels_max (hw_params, &nfo->max_channels);
if (err < 0) {
errmsg = "Cannot get maximum channels count";
goto error_out;
}
err = snd_pcm_hw_params_get_rate_min (hw_params, &nfo->min_rate, NULL);
if (err < 0) {
errmsg = "Cannot get minimum rate";
goto error_out;
}
err = snd_pcm_hw_params_get_rate_max (hw_params, &nfo->max_rate, NULL);
if (err < 0) {
errmsg = "Cannot get maximum rate";
goto error_out;
}
err = snd_pcm_hw_params_get_period_size_min (hw_params, &min_psiz, 0);
if (err < 0) {
errmsg = "Cannot get minimum period size";
goto error_out;
}
err = snd_pcm_hw_params_get_period_size_max (hw_params, &max_psiz, 0);
if (err < 0) {
errmsg = "Cannot get maximum period size";
goto error_out;
}
err = snd_pcm_hw_params_get_buffer_size_min (hw_params, &min_bufz);
if (err < 0) {
errmsg = "Cannot get minimum buffer size";
goto error_out;
}
err = snd_pcm_hw_params_get_buffer_size_max (hw_params, &max_bufz);
if (err < 0) {
errmsg = "Cannot get maximum buffer size";
goto error_out;
}
err = snd_pcm_hw_params_get_periods_min (hw_params, &min_nper, 0);
if (err < 0) {
errmsg = "Cannot get minimum period count";
goto error_out;
}
err = snd_pcm_hw_params_get_periods_max (hw_params, &max_nper, 0);
if (err < 0) {
errmsg = "Cannot get maximum period count";
goto error_out;
}
snd_pcm_close (pcm);
/* see also libs/backends/alsa/zita-alsa-pcmi.cc
* If any debug parameter is set, print device info.
*/
if (getenv ("ZITA_ALSA_PCMI_DEBUG")) {
fprintf (stdout, "ALSA: *%s* device-info\n", play ? "playback" : "capture");
fprintf (stdout, " dev_name : %s\n", device_name);
fprintf (stdout, " channels : %u\n", nfo->max_channels);
fprintf (stdout, " min_rate : %u\n", nfo->min_rate);
fprintf (stdout, " max_rate : %u\n", nfo->max_rate);
fprintf (stdout, " min_psiz : %lu\n", nfo->min_size);
fprintf (stdout, " max_psiz : %lu\n", nfo->max_size);
fprintf (stdout, " min_bufz : %lu\n", min_bufz);
fprintf (stdout, " max_bufz : %lu\n", max_bufz);
fprintf (stdout, " min_nper : %d\n", min_nper);
fprintf (stdout, " max_nper : %d\n", max_nper);
fprintf (stdout, " possible : %lu .. %lu\n", nfo->min_size, nfo->max_size);
}
/* AlsaAudioBackend supports n-periods 2, 3 */
if (min_nper > 2 || max_nper < 3) {
errmsg = "Unsupported period count";
return 1;
}
nfo->min_size = std::max (min_psiz, min_bufz / 3);
nfo->max_size = std::min (max_psiz, max_bufz / 2);
nfo->valid = true;
return 0;
error_out:
fprintf (stderr, "ALSA: %s: %s\n", errmsg.c_str(), snd_strerror (err));
snd_pcm_close (pcm);
return 1;
}