RetroArch/audio/alsa.c
2014-09-11 07:06:20 +02:00

299 lines
7.8 KiB
C

/* RetroArch - A frontend for libretro.
* Copyright (C) 2010-2014 - Hans-Kristian Arntzen
*
* RetroArch 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 Found-
* ation, either version 3 of the License, or (at your option) any later version.
*
* RetroArch 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 RetroArch.
* If not, see <http://www.gnu.org/licenses/>.
*/
#include "../driver.h"
#include <stdlib.h>
#include <alsa/asoundlib.h>
#include "../general.h"
#define TRY_ALSA(x) if (x < 0) { \
goto error; \
}
typedef struct alsa
{
snd_pcm_t *pcm;
size_t buffer_size;
bool nonblock;
bool has_float;
bool can_pause;
bool is_paused;
} alsa_t;
static bool alsa_use_float(void *data)
{
alsa_t *alsa = (alsa_t*)data;
return alsa->has_float;
}
static bool find_float_format(snd_pcm_t *pcm, void *data)
{
snd_pcm_hw_params_t *params = (snd_pcm_hw_params_t*)data;
if (snd_pcm_hw_params_test_format(pcm, params, SND_PCM_FORMAT_FLOAT) == 0)
{
RARCH_LOG("ALSA: Using floating point format.\n");
return true;
}
RARCH_LOG("ALSA: Using signed 16-bit format.\n");
return false;
}
static void *alsa_init(const char *device, unsigned rate, unsigned latency)
{
alsa_t *alsa = (alsa_t*)calloc(1, sizeof(alsa_t));
if (!alsa)
return NULL;
snd_pcm_hw_params_t *params = NULL;
snd_pcm_sw_params_t *sw_params = NULL;
unsigned latency_usec = latency * 1000;
unsigned channels = 2;
unsigned periods = 4;
snd_pcm_format_t format;
const char *alsa_dev = "default";
if (device)
alsa_dev = device;
snd_pcm_uframes_t buffer_size;
TRY_ALSA(snd_pcm_open(
&alsa->pcm, alsa_dev, SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK));
TRY_ALSA(snd_pcm_hw_params_malloc(&params));
alsa->has_float = find_float_format(alsa->pcm, params);
format = alsa->has_float ? SND_PCM_FORMAT_FLOAT : SND_PCM_FORMAT_S16;
TRY_ALSA(snd_pcm_hw_params_any(alsa->pcm, params));
TRY_ALSA(snd_pcm_hw_params_set_access(
alsa->pcm, params, SND_PCM_ACCESS_RW_INTERLEAVED));
TRY_ALSA(snd_pcm_hw_params_set_format(alsa->pcm, params, format));
TRY_ALSA(snd_pcm_hw_params_set_channels(alsa->pcm, params, channels));
TRY_ALSA(snd_pcm_hw_params_set_rate(alsa->pcm, params, rate, 0));
TRY_ALSA(snd_pcm_hw_params_set_buffer_time_near(
alsa->pcm, params, &latency_usec, NULL));
TRY_ALSA(snd_pcm_hw_params_set_periods_near(
alsa->pcm, params, &periods, NULL));
TRY_ALSA(snd_pcm_hw_params(alsa->pcm, params));
/* Shouldn't have to bother with this,
* but some drivers are apparently broken. */
if (snd_pcm_hw_params_get_period_size(params, &buffer_size, NULL))
snd_pcm_hw_params_get_period_size_min(params, &buffer_size, NULL);
RARCH_LOG("ALSA: Period size: %d frames\n", (int)buffer_size);
if (snd_pcm_hw_params_get_buffer_size(params, &buffer_size))
snd_pcm_hw_params_get_buffer_size_max(params, &buffer_size);
RARCH_LOG("ALSA: Buffer size: %d frames\n", (int)buffer_size);
alsa->buffer_size = snd_pcm_frames_to_bytes(alsa->pcm, buffer_size);
alsa->can_pause = snd_pcm_hw_params_can_pause(params);
RARCH_LOG("ALSA: Can pause: %s.\n", alsa->can_pause ? "yes" : "no");
TRY_ALSA(snd_pcm_sw_params_malloc(&sw_params));
TRY_ALSA(snd_pcm_sw_params_current(alsa->pcm, sw_params));
TRY_ALSA(snd_pcm_sw_params_set_start_threshold(
alsa->pcm, sw_params, buffer_size / 2));
TRY_ALSA(snd_pcm_sw_params(alsa->pcm, sw_params));
snd_pcm_hw_params_free(params);
snd_pcm_sw_params_free(sw_params);
return alsa;
error:
RARCH_ERR("ALSA: Failed to initialize...\n");
if (params)
snd_pcm_hw_params_free(params);
if (sw_params)
snd_pcm_sw_params_free(sw_params);
if (alsa)
{
if (alsa->pcm)
snd_pcm_close(alsa->pcm);
free(alsa);
}
return NULL;
}
static ssize_t alsa_write(void *data, const void *buf_, size_t size_)
{
alsa_t *alsa = (alsa_t*)data;
const uint8_t *buf = (const uint8_t*)buf_;
bool eagain_retry = true;
snd_pcm_sframes_t written = 0;
snd_pcm_sframes_t size = snd_pcm_bytes_to_frames(alsa->pcm, size_);
while (size)
{
if (!alsa->nonblock)
{
int rc = snd_pcm_wait(alsa->pcm, -1);
if (rc == -EPIPE || rc == -ESTRPIPE || rc == -EINTR)
{
if (snd_pcm_recover(alsa->pcm, rc, 1) < 0)
{
RARCH_ERR("[ALSA]: (#1) Failed to recover from error (%s)\n",
snd_strerror(rc));
return -1;
}
continue;
}
}
snd_pcm_sframes_t frames = snd_pcm_writei(alsa->pcm, buf, size);
if (frames == -EPIPE || frames == -EINTR || frames == -ESTRPIPE)
{
if (snd_pcm_recover(alsa->pcm, frames, 1) < 0)
{
RARCH_ERR("[ALSA]: (#2) Failed to recover from error (%s)\n",
snd_strerror(frames));
return -1;
}
break;
}
else if (frames == -EAGAIN && !alsa->nonblock)
{
/* Definitely not supposed to happen. */
RARCH_WARN("[ALSA]: poll() was signaled, but EAGAIN returned from write.\n"
"Your ALSA driver might be subtly broken.\n");
if (eagain_retry)
{
eagain_retry = false;
continue;
}
return written;
}
else if (frames == -EAGAIN) /* Expected if we're running nonblock. */
return written;
else if (frames < 0)
{
RARCH_ERR("[ALSA]: Unknown error occured (%s).\n",
snd_strerror(frames));
return -1;
}
written += frames;
buf += (frames << 1) *
(alsa->has_float ? sizeof(float) : sizeof(int16_t));
size -= frames;
}
return written;
}
static bool alsa_stop(void *data)
{
alsa_t *alsa = (alsa_t*)data;
if (alsa->can_pause && !alsa->is_paused)
{
if (snd_pcm_pause(alsa->pcm, 1) == 0)
{
alsa->is_paused = true;
return true;
}
return false;
}
return true;
}
static void alsa_set_nonblock_state(void *data, bool state)
{
alsa_t *alsa = (alsa_t*)data;
alsa->nonblock = state;
}
static bool alsa_start(void *data)
{
alsa_t *alsa = (alsa_t*)data;
if (alsa->can_pause && alsa->is_paused)
{
int ret = snd_pcm_pause(alsa->pcm, 0);
if (ret < 0)
{
RARCH_ERR("[ALSA]: Failed to unpause: %s.\n",
snd_strerror(ret));
return false;
}
else
{
alsa->is_paused = false;
return true;
}
}
return true;
}
static void alsa_free(void *data)
{
alsa_t *alsa = (alsa_t*)data;
if (alsa)
{
if (alsa->pcm)
{
snd_pcm_drop(alsa->pcm);
snd_pcm_close(alsa->pcm);
}
free(alsa);
}
}
static size_t alsa_write_avail(void *data)
{
alsa_t *alsa = (alsa_t*)data;
snd_pcm_sframes_t avail = snd_pcm_avail(alsa->pcm);
if (avail < 0)
{
#if 0
RARCH_WARN("[ALSA]: snd_pcm_avail() failed: %s\n",
snd_strerror(avail));
#endif
return alsa->buffer_size;
}
return snd_pcm_frames_to_bytes(alsa->pcm, avail);
}
static size_t alsa_buffer_size(void *data)
{
alsa_t *alsa = (alsa_t*)data;
return alsa->buffer_size;
}
audio_driver_t audio_alsa = {
alsa_init,
alsa_write,
alsa_stop,
alsa_start,
alsa_set_nonblock_state,
alsa_free,
alsa_use_float,
"alsa",
alsa_write_avail,
alsa_buffer_size,
};