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RetroArch/audio/drivers/alsa.c

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/* RetroArch - A frontend for libretro.
* Copyright (C) 2010-2014 - Hans-Kristian Arntzen
* Copyright (C) 2011-2017 - Daniel De Matteis
*
* 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 <stdlib.h>
#include <lists/string_list.h>
#include <string/stdstring.h>
#include <alsa/asoundlib.h>
#include "../audio_driver.h"
#include "../../verbosity.h"
typedef struct alsa
{
snd_pcm_t *pcm;
size_t buffer_size;
bool nonblock;
unsigned int frame_bits;
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,
unsigned block_frames,
unsigned *new_rate)
{
snd_pcm_format_t format;
snd_pcm_uframes_t buffer_size;
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;
unsigned orig_rate = rate;
const char *alsa_dev = "default";
alsa_t *alsa = (alsa_t*)calloc(1, sizeof(alsa_t));
if (!alsa)
return NULL;
if (device)
alsa_dev = device;
if (snd_pcm_open(
&alsa->pcm, alsa_dev, SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK) < 0)
goto error;
if (snd_pcm_hw_params_malloc(&params) < 0)
goto error;
alsa->has_float = find_float_format(alsa->pcm, params);
format = alsa->has_float ? SND_PCM_FORMAT_FLOAT : SND_PCM_FORMAT_S16;
if (snd_pcm_hw_params_any(alsa->pcm, params) < 0)
goto error;
if (snd_pcm_hw_params_set_access(
alsa->pcm, params, SND_PCM_ACCESS_RW_INTERLEAVED) < 0)
goto error;
/* channels hardcoded to 2 for now */
alsa->frame_bits = snd_pcm_format_physical_width(format) * 2;
if (snd_pcm_hw_params_set_format(alsa->pcm, params, format) < 0)
goto error;
if (snd_pcm_hw_params_set_channels(alsa->pcm, params, channels) < 0)
goto error;
/* Don't allow rate resampling when probing for the default rate (but ignore if this call fails) */
snd_pcm_hw_params_set_rate_resample(alsa->pcm, params, 0 );
if (snd_pcm_hw_params_set_rate_near(alsa->pcm, params, &rate, 0) < 0)
goto error;
if (rate != orig_rate)
*new_rate = rate;
if (snd_pcm_hw_params_set_buffer_time_near(
alsa->pcm, params, &latency_usec, NULL) < 0)
goto error;
if (snd_pcm_hw_params_set_periods_near(
alsa->pcm, params, &periods, NULL) < 0)
goto error;
if (snd_pcm_hw_params(alsa->pcm, params) < 0)
goto error;
/* 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");
if (snd_pcm_sw_params_malloc(&sw_params) < 0)
goto error;
if (snd_pcm_sw_params_current(alsa->pcm, sw_params) < 0)
goto error;
if (snd_pcm_sw_params_set_start_threshold(
alsa->pcm, sw_params, buffer_size / 2) < 0)
goto error;
if (snd_pcm_sw_params(alsa->pcm, sw_params) < 0)
goto error;
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);
snd_config_update_free_global();
}
free(alsa);
}
return NULL;
}
#define BYTES_TO_FRAMES(bytes, frame_bits) ((bytes) * 8 / frame_bits)
#define FRAMES_TO_BYTES(frames, frame_bits) ((frames) * frame_bits / 8)
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_;
snd_pcm_sframes_t written = 0;
snd_pcm_sframes_t size = BYTES_TO_FRAMES(size_, alsa->frame_bits);
size_t frames_size = alsa->has_float ? sizeof(float) : sizeof(int16_t);
if (alsa->nonblock)
{
while (size)
{
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)
return -1;
break;
}
else if (frames == -EAGAIN)
break;
else if (frames < 0)
return -1;
written += frames;
buf += (frames << 1) * frames_size;
size -= frames;
}
}
else
{
bool eagain_retry = true;
while (size)
{
snd_pcm_sframes_t frames;
int rc = snd_pcm_wait(alsa->pcm, -1);
if (rc == -EPIPE || rc == -ESTRPIPE || rc == -EINTR)
{
if (snd_pcm_recover(alsa->pcm, rc, 1) < 0)
return -1;
continue;
}
frames = snd_pcm_writei(alsa->pcm, buf, size);
if (frames == -EPIPE || frames == -EINTR || frames == -ESTRPIPE)
{
if (snd_pcm_recover(alsa->pcm, frames, 1) < 0)
return -1;
break;
}
else if (frames == -EAGAIN)
{
/* Definitely not supposed to happen. */
if (eagain_retry)
{
eagain_retry = false;
continue;
}
break;
}
else if (frames < 0)
return -1;
written += frames;
buf += (frames << 1) * frames_size;
size -= frames;
}
}
return written;
}
static bool alsa_alive(void *data)
{
alsa_t *alsa = (alsa_t*)data;
if (!alsa)
return false;
return !alsa->is_paused;
}
static bool alsa_stop(void *data)
{
alsa_t *alsa = (alsa_t*)data;
if (alsa->can_pause
&& !alsa->is_paused)
{
int ret = snd_pcm_pause(alsa->pcm, 1);
if (ret < 0)
return false;
alsa->is_paused = true;
}
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, bool is_shutdown)
{
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;
}
alsa->is_paused = false;
}
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);
snd_config_update_free_global();
}
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)
return alsa->buffer_size;
return FRAMES_TO_BYTES(avail, alsa->frame_bits);
}
static size_t alsa_buffer_size(void *data)
{
alsa_t *alsa = (alsa_t*)data;
return alsa->buffer_size;
}
static void *alsa_device_list_new(void *data)
{
void **hints, **n;
union string_list_elem_attr attr;
struct string_list *s = string_list_new();
if (!s)
return NULL;
attr.i = 0;
if (snd_device_name_hint(-1, "pcm", &hints) != 0)
goto error;
n = hints;
while (*n != NULL)
{
char *name = snd_device_name_get_hint(*n, "NAME");
char *io = snd_device_name_get_hint(*n, "IOID");
char *desc = snd_device_name_get_hint(*n, "DESC");
/* description of device IOID - input / output identifcation
* ("Input" or "Output"), NULL means both) */
if (!io || (string_is_equal_fast(io, "Output", 6)))
string_list_append(s, name, attr);
if (name)
free(name);
if (io)
free(io);
if (desc)
free(desc);
n++;
}
/* free hint buffer too */
snd_device_name_free_hint(hints);
return s;
error:
string_list_free(s);
return NULL;
}
static void alsa_device_list_free(void *data, void *array_list_data)
{
struct string_list *s = (struct string_list*)array_list_data;
if (!s)
return;
string_list_free(s);
}
audio_driver_t audio_alsa = {
alsa_init,
alsa_write,
alsa_stop,
alsa_start,
alsa_alive,
alsa_set_nonblock_state,
alsa_free,
alsa_use_float,
"alsa",
alsa_device_list_new,
alsa_device_list_free,
alsa_write_avail,
alsa_buffer_size,
};
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