SDL_alsa_audio.c
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/*
Simple DirectMedia Layer
Copyright (C) 1997-2018 Sam Lantinga <slouken@libsdl.org>
This software is provided 'as-is', without any express or implied
warranty. In no event will the authors be held liable for any damages
arising from the use of this software.
Permission is granted to anyone to use this software for any purpose,
including commercial applications, and to alter it and redistribute it
freely, subject to the following restrictions:
1. The origin of this software must not be misrepresented; you must not
claim that you wrote the original software. If you use this software
in a product, an acknowledgment in the product documentation would be
appreciated but is not required.
2. Altered source versions must be plainly marked as such, and must not be
misrepresented as being the original software.
3. This notice may not be removed or altered from any source distribution.
*/
#include "../../SDL_internal.h"
#if SDL_AUDIO_DRIVER_ALSA
/* Allow access to a raw mixing buffer */
#include <sys/types.h>
#include <signal.h> /* For kill() */
#include <string.h>
#include "SDL_assert.h"
#include "SDL_timer.h"
#include "SDL_audio.h"
#include "../SDL_audio_c.h"
#include "SDL_alsa_audio.h"
#ifdef SDL_AUDIO_DRIVER_ALSA_DYNAMIC
#include "SDL_loadso.h"
#endif
static int (*ALSA_snd_pcm_open)
(snd_pcm_t **, const char *, snd_pcm_stream_t, int);
static int (*ALSA_snd_pcm_close) (snd_pcm_t * pcm);
static snd_pcm_sframes_t (*ALSA_snd_pcm_writei)
(snd_pcm_t *, const void *, snd_pcm_uframes_t);
static snd_pcm_sframes_t (*ALSA_snd_pcm_readi)
(snd_pcm_t *, void *, snd_pcm_uframes_t);
static int (*ALSA_snd_pcm_recover) (snd_pcm_t *, int, int);
static int (*ALSA_snd_pcm_prepare) (snd_pcm_t *);
static int (*ALSA_snd_pcm_drain) (snd_pcm_t *);
static const char *(*ALSA_snd_strerror) (int);
static size_t(*ALSA_snd_pcm_hw_params_sizeof) (void);
static size_t(*ALSA_snd_pcm_sw_params_sizeof) (void);
static void (*ALSA_snd_pcm_hw_params_copy)
(snd_pcm_hw_params_t *, const snd_pcm_hw_params_t *);
static int (*ALSA_snd_pcm_hw_params_any) (snd_pcm_t *, snd_pcm_hw_params_t *);
static int (*ALSA_snd_pcm_hw_params_set_access)
(snd_pcm_t *, snd_pcm_hw_params_t *, snd_pcm_access_t);
static int (*ALSA_snd_pcm_hw_params_set_format)
(snd_pcm_t *, snd_pcm_hw_params_t *, snd_pcm_format_t);
static int (*ALSA_snd_pcm_hw_params_set_channels)
(snd_pcm_t *, snd_pcm_hw_params_t *, unsigned int);
static int (*ALSA_snd_pcm_hw_params_get_channels)
(const snd_pcm_hw_params_t *, unsigned int *);
static int (*ALSA_snd_pcm_hw_params_set_rate_near)
(snd_pcm_t *, snd_pcm_hw_params_t *, unsigned int *, int *);
static int (*ALSA_snd_pcm_hw_params_set_period_size_near)
(snd_pcm_t *, snd_pcm_hw_params_t *, snd_pcm_uframes_t *, int *);
static int (*ALSA_snd_pcm_hw_params_get_period_size)
(const snd_pcm_hw_params_t *, snd_pcm_uframes_t *, int *);
static int (*ALSA_snd_pcm_hw_params_set_periods_near)
(snd_pcm_t *, snd_pcm_hw_params_t *, unsigned int *, int *);
static int (*ALSA_snd_pcm_hw_params_get_periods)
(const snd_pcm_hw_params_t *, unsigned int *, int *);
static int (*ALSA_snd_pcm_hw_params_set_buffer_size_near)
(snd_pcm_t *pcm, snd_pcm_hw_params_t *, snd_pcm_uframes_t *);
static int (*ALSA_snd_pcm_hw_params_get_buffer_size)
(const snd_pcm_hw_params_t *, snd_pcm_uframes_t *);
static int (*ALSA_snd_pcm_hw_params) (snd_pcm_t *, snd_pcm_hw_params_t *);
static int (*ALSA_snd_pcm_sw_params_current) (snd_pcm_t *,
snd_pcm_sw_params_t *);
static int (*ALSA_snd_pcm_sw_params_set_start_threshold)
(snd_pcm_t *, snd_pcm_sw_params_t *, snd_pcm_uframes_t);
static int (*ALSA_snd_pcm_sw_params) (snd_pcm_t *, snd_pcm_sw_params_t *);
static int (*ALSA_snd_pcm_nonblock) (snd_pcm_t *, int);
static int (*ALSA_snd_pcm_wait)(snd_pcm_t *, int);
static int (*ALSA_snd_pcm_sw_params_set_avail_min)
(snd_pcm_t *, snd_pcm_sw_params_t *, snd_pcm_uframes_t);
static int (*ALSA_snd_pcm_reset)(snd_pcm_t *);
static int (*ALSA_snd_device_name_hint) (int, const char *, void ***);
static char* (*ALSA_snd_device_name_get_hint) (const void *, const char *);
static int (*ALSA_snd_device_name_free_hint) (void **);
#ifdef SND_CHMAP_API_VERSION
static snd_pcm_chmap_t* (*ALSA_snd_pcm_get_chmap) (snd_pcm_t *);
static int (*ALSA_snd_pcm_chmap_print) (const snd_pcm_chmap_t *map, size_t maxlen, char *buf);
#endif
#ifdef SDL_AUDIO_DRIVER_ALSA_DYNAMIC
#define snd_pcm_hw_params_sizeof ALSA_snd_pcm_hw_params_sizeof
#define snd_pcm_sw_params_sizeof ALSA_snd_pcm_sw_params_sizeof
static const char *alsa_library = SDL_AUDIO_DRIVER_ALSA_DYNAMIC;
static void *alsa_handle = NULL;
static int
load_alsa_sym(const char *fn, void **addr)
{
*addr = SDL_LoadFunction(alsa_handle, fn);
if (*addr == NULL) {
/* Don't call SDL_SetError(): SDL_LoadFunction already did. */
return 0;
}
return 1;
}
/* cast funcs to char* first, to please GCC's strict aliasing rules. */
#define SDL_ALSA_SYM(x) \
if (!load_alsa_sym(#x, (void **) (char *) &ALSA_##x)) return -1
#else
#define SDL_ALSA_SYM(x) ALSA_##x = x
#endif
static int
load_alsa_syms(void)
{
SDL_ALSA_SYM(snd_pcm_open);
SDL_ALSA_SYM(snd_pcm_close);
SDL_ALSA_SYM(snd_pcm_writei);
SDL_ALSA_SYM(snd_pcm_readi);
SDL_ALSA_SYM(snd_pcm_recover);
SDL_ALSA_SYM(snd_pcm_prepare);
SDL_ALSA_SYM(snd_pcm_drain);
SDL_ALSA_SYM(snd_strerror);
SDL_ALSA_SYM(snd_pcm_hw_params_sizeof);
SDL_ALSA_SYM(snd_pcm_sw_params_sizeof);
SDL_ALSA_SYM(snd_pcm_hw_params_copy);
SDL_ALSA_SYM(snd_pcm_hw_params_any);
SDL_ALSA_SYM(snd_pcm_hw_params_set_access);
SDL_ALSA_SYM(snd_pcm_hw_params_set_format);
SDL_ALSA_SYM(snd_pcm_hw_params_set_channels);
SDL_ALSA_SYM(snd_pcm_hw_params_get_channels);
SDL_ALSA_SYM(snd_pcm_hw_params_set_rate_near);
SDL_ALSA_SYM(snd_pcm_hw_params_set_period_size_near);
SDL_ALSA_SYM(snd_pcm_hw_params_get_period_size);
SDL_ALSA_SYM(snd_pcm_hw_params_set_periods_near);
SDL_ALSA_SYM(snd_pcm_hw_params_get_periods);
SDL_ALSA_SYM(snd_pcm_hw_params_set_buffer_size_near);
SDL_ALSA_SYM(snd_pcm_hw_params_get_buffer_size);
SDL_ALSA_SYM(snd_pcm_hw_params);
SDL_ALSA_SYM(snd_pcm_sw_params_current);
SDL_ALSA_SYM(snd_pcm_sw_params_set_start_threshold);
SDL_ALSA_SYM(snd_pcm_sw_params);
SDL_ALSA_SYM(snd_pcm_nonblock);
SDL_ALSA_SYM(snd_pcm_wait);
SDL_ALSA_SYM(snd_pcm_sw_params_set_avail_min);
SDL_ALSA_SYM(snd_pcm_reset);
SDL_ALSA_SYM(snd_device_name_hint);
SDL_ALSA_SYM(snd_device_name_get_hint);
SDL_ALSA_SYM(snd_device_name_free_hint);
#ifdef SND_CHMAP_API_VERSION
SDL_ALSA_SYM(snd_pcm_get_chmap);
SDL_ALSA_SYM(snd_pcm_chmap_print);
#endif
return 0;
}
#undef SDL_ALSA_SYM
#ifdef SDL_AUDIO_DRIVER_ALSA_DYNAMIC
static void
UnloadALSALibrary(void)
{
if (alsa_handle != NULL) {
SDL_UnloadObject(alsa_handle);
alsa_handle = NULL;
}
}
static int
LoadALSALibrary(void)
{
int retval = 0;
if (alsa_handle == NULL) {
alsa_handle = SDL_LoadObject(alsa_library);
if (alsa_handle == NULL) {
retval = -1;
/* Don't call SDL_SetError(): SDL_LoadObject already did. */
} else {
retval = load_alsa_syms();
if (retval < 0) {
UnloadALSALibrary();
}
}
}
return retval;
}
#else
static void
UnloadALSALibrary(void)
{
}
static int
LoadALSALibrary(void)
{
load_alsa_syms();
return 0;
}
#endif /* SDL_AUDIO_DRIVER_ALSA_DYNAMIC */
static const char *
get_audio_device(void *handle, const int channels)
{
const char *device;
if (handle != NULL) {
return (const char *) handle;
}
/* !!! FIXME: we also check "SDL_AUDIO_DEVICE_NAME" at the higher level. */
device = SDL_getenv("AUDIODEV"); /* Is there a standard variable name? */
if (device != NULL) {
return device;
}
if (channels == 6) {
return "plug:surround51";
} else if (channels == 4) {
return "plug:surround40";
}
return "default";
}
/* This function waits until it is possible to write a full sound buffer */
static void
ALSA_WaitDevice(_THIS)
{
/* We're in blocking mode, so there's nothing to do here */
}
/* !!! FIXME: is there a channel swizzler in alsalib instead? */
/*
* http://bugzilla.libsdl.org/show_bug.cgi?id=110
* "For Linux ALSA, this is FL-FR-RL-RR-C-LFE
* and for Windows DirectX [and CoreAudio], this is FL-FR-C-LFE-RL-RR"
*/
#define SWIZ6(T, buf, numframes) \
T *ptr = (T *) buf; \
Uint32 i; \
for (i = 0; i < numframes; i++, ptr += 6) { \
T tmp; \
tmp = ptr[2]; ptr[2] = ptr[4]; ptr[4] = tmp; \
tmp = ptr[3]; ptr[3] = ptr[5]; ptr[5] = tmp; \
}
static void
swizzle_alsa_channels_6_64bit(void *buffer, Uint32 bufferlen)
{
SWIZ6(Uint64, buffer, bufferlen);
}
static void
swizzle_alsa_channels_6_32bit(void *buffer, Uint32 bufferlen)
{
SWIZ6(Uint32, buffer, bufferlen);
}
static void
swizzle_alsa_channels_6_16bit(void *buffer, Uint32 bufferlen)
{
SWIZ6(Uint16, buffer, bufferlen);
}
static void
swizzle_alsa_channels_6_8bit(void *buffer, Uint32 bufferlen)
{
SWIZ6(Uint8, buffer, bufferlen);
}
#undef SWIZ6
/*
* Called right before feeding this->hidden->mixbuf to the hardware. Swizzle
* channels from Windows/Mac order to the format alsalib will want.
*/
static void
swizzle_alsa_channels(_THIS, void *buffer, Uint32 bufferlen)
{
if (this->spec.channels == 6) {
switch (SDL_AUDIO_BITSIZE(this->spec.format)) {
case 8: swizzle_alsa_channels_6_8bit(buffer, bufferlen); break;
case 16: swizzle_alsa_channels_6_16bit(buffer, bufferlen); break;
case 32: swizzle_alsa_channels_6_32bit(buffer, bufferlen); break;
case 64: swizzle_alsa_channels_6_64bit(buffer, bufferlen); break;
default: SDL_assert(!"unhandled bitsize"); break;
}
}
/* !!! FIXME: update this for 7.1 if needed, later. */
}
#ifdef SND_CHMAP_API_VERSION
/* Some devices have the right channel map, no swizzling necessary */
static void
no_swizzle(_THIS, void *buffer, Uint32 bufferlen)
{
return;
}
#endif /* SND_CHMAP_API_VERSION */
static void
ALSA_PlayDevice(_THIS)
{
const Uint8 *sample_buf = (const Uint8 *) this->hidden->mixbuf;
const int frame_size = (((int) SDL_AUDIO_BITSIZE(this->spec.format)) / 8) *
this->spec.channels;
snd_pcm_uframes_t frames_left = ((snd_pcm_uframes_t) this->spec.samples);
this->hidden->swizzle_func(this, this->hidden->mixbuf, frames_left);
while ( frames_left > 0 && SDL_AtomicGet(&this->enabled) ) {
int status = ALSA_snd_pcm_writei(this->hidden->pcm_handle,
sample_buf, frames_left);
if (status < 0) {
if (status == -EAGAIN) {
/* Apparently snd_pcm_recover() doesn't handle this case -
does it assume snd_pcm_wait() above? */
SDL_Delay(1);
continue;
}
status = ALSA_snd_pcm_recover(this->hidden->pcm_handle, status, 0);
if (status < 0) {
/* Hmm, not much we can do - abort */
fprintf(stderr, "ALSA write failed (unrecoverable): %s\n",
ALSA_snd_strerror(status));
SDL_OpenedAudioDeviceDisconnected(this);
return;
}
continue;
}
else if (status == 0) {
/* No frames were written (no available space in pcm device).
Allow other threads to catch up. */
Uint32 delay = (frames_left / 2 * 1000) / this->spec.freq;
SDL_Delay(delay);
}
sample_buf += status * frame_size;
frames_left -= status;
}
}
static Uint8 *
ALSA_GetDeviceBuf(_THIS)
{
return (this->hidden->mixbuf);
}
static int
ALSA_CaptureFromDevice(_THIS, void *buffer, int buflen)
{
Uint8 *sample_buf = (Uint8 *) buffer;
const int frame_size = (((int) SDL_AUDIO_BITSIZE(this->spec.format)) / 8) *
this->spec.channels;
const int total_frames = buflen / frame_size;
snd_pcm_uframes_t frames_left = total_frames;
snd_pcm_uframes_t wait_time = frame_size / 2;
SDL_assert((buflen % frame_size) == 0);
while ( frames_left > 0 && SDL_AtomicGet(&this->enabled) ) {
int status;
status = ALSA_snd_pcm_readi(this->hidden->pcm_handle,
sample_buf, frames_left);
if (status == -EAGAIN) {
ALSA_snd_pcm_wait(this->hidden->pcm_handle, wait_time);
status = 0;
}
else if (status < 0) {
/*printf("ALSA: capture error %d\n", status);*/
status = ALSA_snd_pcm_recover(this->hidden->pcm_handle, status, 0);
if (status < 0) {
/* Hmm, not much we can do - abort */
fprintf(stderr, "ALSA read failed (unrecoverable): %s\n",
ALSA_snd_strerror(status));
return -1;
}
continue;
}
/*printf("ALSA: captured %d bytes\n", status * frame_size);*/
sample_buf += status * frame_size;
frames_left -= status;
}
this->hidden->swizzle_func(this, buffer, total_frames - frames_left);
return (total_frames - frames_left) * frame_size;
}
static void
ALSA_FlushCapture(_THIS)
{
ALSA_snd_pcm_reset(this->hidden->pcm_handle);
}
static void
ALSA_CloseDevice(_THIS)
{
if (this->hidden->pcm_handle) {
/* Wait for the submitted audio to drain
ALSA_snd_pcm_drop() can hang, so don't use that.
*/
Uint32 delay = ((this->spec.samples * 1000) / this->spec.freq) * 2;
SDL_Delay(delay);
ALSA_snd_pcm_close(this->hidden->pcm_handle);
}
SDL_free(this->hidden->mixbuf);
SDL_free(this->hidden);
}
static int
ALSA_finalize_hardware(_THIS, snd_pcm_hw_params_t *hwparams, int override)
{
int status;
snd_pcm_uframes_t bufsize;
/* "set" the hardware with the desired parameters */
status = ALSA_snd_pcm_hw_params(this->hidden->pcm_handle, hwparams);
if ( status < 0 ) {
return(-1);
}
/* Get samples for the actual buffer size */
status = ALSA_snd_pcm_hw_params_get_buffer_size(hwparams, &bufsize);
if ( status < 0 ) {
return(-1);
}
if ( !override && bufsize != this->spec.samples * 2 ) {
return(-1);
}
/* !!! FIXME: Is this safe to do? */
this->spec.samples = bufsize / 2;
/* This is useful for debugging */
if ( SDL_getenv("SDL_AUDIO_ALSA_DEBUG") ) {
snd_pcm_uframes_t persize = 0;
unsigned int periods = 0;
ALSA_snd_pcm_hw_params_get_period_size(hwparams, &persize, NULL);
ALSA_snd_pcm_hw_params_get_periods(hwparams, &periods, NULL);
fprintf(stderr,
"ALSA: period size = %ld, periods = %u, buffer size = %lu\n",
persize, periods, bufsize);
}
return(0);
}
static int
ALSA_set_period_size(_THIS, snd_pcm_hw_params_t *params, int override)
{
const char *env;
int status;
snd_pcm_hw_params_t *hwparams;
snd_pcm_uframes_t frames;
unsigned int periods;
/* Copy the hardware parameters for this setup */
snd_pcm_hw_params_alloca(&hwparams);
ALSA_snd_pcm_hw_params_copy(hwparams, params);
if ( !override ) {
env = SDL_getenv("SDL_AUDIO_ALSA_SET_PERIOD_SIZE");
if ( env ) {
override = SDL_atoi(env);
if ( override == 0 ) {
return(-1);
}
}
}
frames = this->spec.samples;
status = ALSA_snd_pcm_hw_params_set_period_size_near(
this->hidden->pcm_handle, hwparams, &frames, NULL);
if ( status < 0 ) {
return(-1);
}
periods = 2;
status = ALSA_snd_pcm_hw_params_set_periods_near(
this->hidden->pcm_handle, hwparams, &periods, NULL);
if ( status < 0 ) {
return(-1);
}
return ALSA_finalize_hardware(this, hwparams, override);
}
static int
ALSA_set_buffer_size(_THIS, snd_pcm_hw_params_t *params, int override)
{
const char *env;
int status;
snd_pcm_hw_params_t *hwparams;
snd_pcm_uframes_t frames;
/* Copy the hardware parameters for this setup */
snd_pcm_hw_params_alloca(&hwparams);
ALSA_snd_pcm_hw_params_copy(hwparams, params);
if ( !override ) {
env = SDL_getenv("SDL_AUDIO_ALSA_SET_BUFFER_SIZE");
if ( env ) {
override = SDL_atoi(env);
if ( override == 0 ) {
return(-1);
}
}
}
frames = this->spec.samples * 2;
status = ALSA_snd_pcm_hw_params_set_buffer_size_near(
this->hidden->pcm_handle, hwparams, &frames);
if ( status < 0 ) {
return(-1);
}
return ALSA_finalize_hardware(this, hwparams, override);
}
static int
ALSA_OpenDevice(_THIS, void *handle, const char *devname, int iscapture)
{
int status = 0;
snd_pcm_t *pcm_handle = NULL;
snd_pcm_hw_params_t *hwparams = NULL;
snd_pcm_sw_params_t *swparams = NULL;
snd_pcm_format_t format = 0;
SDL_AudioFormat test_format = 0;
unsigned int rate = 0;
unsigned int channels = 0;
#ifdef SND_CHMAP_API_VERSION
snd_pcm_chmap_t *chmap;
char chmap_str[64];
#endif
/* Initialize all variables that we clean on shutdown */
this->hidden = (struct SDL_PrivateAudioData *)
SDL_malloc((sizeof *this->hidden));
if (this->hidden == NULL) {
return SDL_OutOfMemory();
}
SDL_zerop(this->hidden);
/* Open the audio device */
/* Name of device should depend on # channels in spec */
status = ALSA_snd_pcm_open(&pcm_handle,
get_audio_device(handle, this->spec.channels),
iscapture ? SND_PCM_STREAM_CAPTURE : SND_PCM_STREAM_PLAYBACK,
SND_PCM_NONBLOCK);
if (status < 0) {
return SDL_SetError("ALSA: Couldn't open audio device: %s",
ALSA_snd_strerror(status));
}
this->hidden->pcm_handle = pcm_handle;
/* Figure out what the hardware is capable of */
snd_pcm_hw_params_alloca(&hwparams);
status = ALSA_snd_pcm_hw_params_any(pcm_handle, hwparams);
if (status < 0) {
return SDL_SetError("ALSA: Couldn't get hardware config: %s",
ALSA_snd_strerror(status));
}
/* SDL only uses interleaved sample output */
status = ALSA_snd_pcm_hw_params_set_access(pcm_handle, hwparams,
SND_PCM_ACCESS_RW_INTERLEAVED);
if (status < 0) {
return SDL_SetError("ALSA: Couldn't set interleaved access: %s",
ALSA_snd_strerror(status));
}
/* Try for a closest match on audio format */
status = -1;
for (test_format = SDL_FirstAudioFormat(this->spec.format);
test_format && (status < 0);) {
status = 0; /* if we can't support a format, it'll become -1. */
switch (test_format) {
case AUDIO_U8:
format = SND_PCM_FORMAT_U8;
break;
case AUDIO_S8:
format = SND_PCM_FORMAT_S8;
break;
case AUDIO_S16LSB:
format = SND_PCM_FORMAT_S16_LE;
break;
case AUDIO_S16MSB:
format = SND_PCM_FORMAT_S16_BE;
break;
case AUDIO_U16LSB:
format = SND_PCM_FORMAT_U16_LE;
break;
case AUDIO_U16MSB:
format = SND_PCM_FORMAT_U16_BE;
break;
case AUDIO_S32LSB:
format = SND_PCM_FORMAT_S32_LE;
break;
case AUDIO_S32MSB:
format = SND_PCM_FORMAT_S32_BE;
break;
case AUDIO_F32LSB:
format = SND_PCM_FORMAT_FLOAT_LE;
break;
case AUDIO_F32MSB:
format = SND_PCM_FORMAT_FLOAT_BE;
break;
default:
status = -1;
break;
}
if (status >= 0) {
status = ALSA_snd_pcm_hw_params_set_format(pcm_handle,
hwparams, format);
}
if (status < 0) {
test_format = SDL_NextAudioFormat();
}
}
if (status < 0) {
return SDL_SetError("ALSA: Couldn't find any hardware audio formats");
}
this->spec.format = test_format;
/* Validate number of channels and determine if swizzling is necessary
* Assume original swizzling, until proven otherwise.
*/
this->hidden->swizzle_func = swizzle_alsa_channels;
#ifdef SND_CHMAP_API_VERSION
chmap = ALSA_snd_pcm_get_chmap(pcm_handle);
if (chmap) {
ALSA_snd_pcm_chmap_print(chmap, sizeof(chmap_str), chmap_str);
if (SDL_strcmp("FL FR FC LFE RL RR", chmap_str) == 0 ||
SDL_strcmp("FL FR FC LFE SL SR", chmap_str) == 0) {
this->hidden->swizzle_func = no_swizzle;
}
free(chmap);
}
#endif /* SND_CHMAP_API_VERSION */
/* Set the number of channels */
status = ALSA_snd_pcm_hw_params_set_channels(pcm_handle, hwparams,
this->spec.channels);
channels = this->spec.channels;
if (status < 0) {
status = ALSA_snd_pcm_hw_params_get_channels(hwparams, &channels);
if (status < 0) {
return SDL_SetError("ALSA: Couldn't set audio channels");
}
this->spec.channels = channels;
}
/* Set the audio rate */
rate = this->spec.freq;
status = ALSA_snd_pcm_hw_params_set_rate_near(pcm_handle, hwparams,
&rate, NULL);
if (status < 0) {
return SDL_SetError("ALSA: Couldn't set audio frequency: %s",
ALSA_snd_strerror(status));
}
this->spec.freq = rate;
/* Set the buffer size, in samples */
if ( ALSA_set_period_size(this, hwparams, 0) < 0 &&
ALSA_set_buffer_size(this, hwparams, 0) < 0 ) {
/* Failed to set desired buffer size, do the best you can... */
status = ALSA_set_period_size(this, hwparams, 1);
if (status < 0) {
return SDL_SetError("Couldn't set hardware audio parameters: %s", ALSA_snd_strerror(status));
}
}
/* Set the software parameters */
snd_pcm_sw_params_alloca(&swparams);
status = ALSA_snd_pcm_sw_params_current(pcm_handle, swparams);
if (status < 0) {
return SDL_SetError("ALSA: Couldn't get software config: %s",
ALSA_snd_strerror(status));
}
status = ALSA_snd_pcm_sw_params_set_avail_min(pcm_handle, swparams, this->spec.samples);
if (status < 0) {
return SDL_SetError("Couldn't set minimum available samples: %s",
ALSA_snd_strerror(status));
}
status =
ALSA_snd_pcm_sw_params_set_start_threshold(pcm_handle, swparams, 1);
if (status < 0) {
return SDL_SetError("ALSA: Couldn't set start threshold: %s",
ALSA_snd_strerror(status));
}
status = ALSA_snd_pcm_sw_params(pcm_handle, swparams);
if (status < 0) {
return SDL_SetError("Couldn't set software audio parameters: %s",
ALSA_snd_strerror(status));
}
/* Calculate the final parameters for this audio specification */
SDL_CalculateAudioSpec(&this->spec);
/* Allocate mixing buffer */
if (!iscapture) {
this->hidden->mixlen = this->spec.size;
this->hidden->mixbuf = (Uint8 *) SDL_malloc(this->hidden->mixlen);
if (this->hidden->mixbuf == NULL) {
return SDL_OutOfMemory();
}
SDL_memset(this->hidden->mixbuf, this->spec.silence, this->hidden->mixlen);
}
if (!iscapture) {
ALSA_snd_pcm_nonblock(pcm_handle, 0);
}
/* We're ready to rock and roll. :-) */
return 0;
}
typedef struct ALSA_Device
{
char *name;
SDL_bool iscapture;
struct ALSA_Device *next;
} ALSA_Device;
static void
add_device(const int iscapture, const char *name, void *hint, ALSA_Device **pSeen)
{
ALSA_Device *dev = SDL_malloc(sizeof (ALSA_Device));
char *desc;
char *handle = NULL;
char *ptr;
if (!dev) {
return;
}
/* Not all alsa devices are enumerable via snd_device_name_get_hint
(i.e. bluetooth devices). Therefore if hint is passed in to this
function as NULL, assume name contains desc.
Make sure not to free the storage associated with desc in this case */
if (hint) {
desc = ALSA_snd_device_name_get_hint(hint, "DESC");
if (!desc) {
SDL_free(dev);
return;
}
} else {
desc = (char *) name;
}
SDL_assert(name != NULL);
/* some strings have newlines, like "HDA NVidia, HDMI 0\nHDMI Audio Output".
just chop the extra lines off, this seems to get a reasonable device
name without extra details. */
if ((ptr = strchr(desc, '\n')) != NULL) {
*ptr = '\0';
}
/*printf("ALSA: adding %s device '%s' (%s)\n", iscapture ? "capture" : "output", name, desc);*/
handle = SDL_strdup(name);
if (!handle) {
if (hint) {
free(desc);
}
SDL_free(dev);
return;
}
SDL_AddAudioDevice(iscapture, desc, handle);
if (hint)
free(desc);
dev->name = handle;
dev->iscapture = iscapture;
dev->next = *pSeen;
*pSeen = dev;
}
static SDL_atomic_t ALSA_hotplug_shutdown;
static SDL_Thread *ALSA_hotplug_thread;
static int SDLCALL
ALSA_HotplugThread(void *arg)
{
SDL_sem *first_run_semaphore = (SDL_sem *) arg;
ALSA_Device *devices = NULL;
ALSA_Device *next;
ALSA_Device *dev;
Uint32 ticks;
SDL_SetThreadPriority(SDL_THREAD_PRIORITY_LOW);
while (!SDL_AtomicGet(&ALSA_hotplug_shutdown)) {
void **hints = NULL;
ALSA_Device *unseen;
ALSA_Device *seen;
ALSA_Device *prev;
if (ALSA_snd_device_name_hint(-1, "pcm", &hints) != -1) {
int i, j;
const char *match = NULL;
int bestmatch = 0xFFFF;
size_t match_len = 0;
int defaultdev = -1;
static const char * const prefixes[] = {
"hw:", "sysdefault:", "default:", NULL
};
unseen = devices;
seen = NULL;
/* Apparently there are several different ways that ALSA lists
actual hardware. It could be prefixed with "hw:" or "default:"
or "sysdefault:" and maybe others. Go through the list and see
if we can find a preferred prefix for the system. */
for (i = 0; hints[i]; i++) {
char *name = ALSA_snd_device_name_get_hint(hints[i], "NAME");
if (!name) {
continue;
}
/* full name, not a prefix */
if ((defaultdev == -1) && (SDL_strcmp(name, "default") == 0)) {
defaultdev = i;
}
for (j = 0; prefixes[j]; j++) {
const char *prefix = prefixes[j];
const size_t prefixlen = SDL_strlen(prefix);
if (SDL_strncmp(name, prefix, prefixlen) == 0) {
if (j < bestmatch) {
bestmatch = j;
match = prefix;
match_len = prefixlen;
}
}
}
free(name);
}
/* look through the list of device names to find matches */
for (i = 0; hints[i]; i++) {
char *name;
/* if we didn't find a device name prefix we like at all... */
if ((!match) && (defaultdev != i)) {
continue; /* ...skip anything that isn't the default device. */
}
name = ALSA_snd_device_name_get_hint(hints[i], "NAME");
if (!name) {
continue;
}
/* only want physical hardware interfaces */
if (!match || (SDL_strncmp(name, match, match_len) == 0)) {
char *ioid = ALSA_snd_device_name_get_hint(hints[i], "IOID");
const SDL_bool isoutput = (ioid == NULL) || (SDL_strcmp(ioid, "Output") == 0);
const SDL_bool isinput = (ioid == NULL) || (SDL_strcmp(ioid, "Input") == 0);
SDL_bool have_output = SDL_FALSE;
SDL_bool have_input = SDL_FALSE;
free(ioid);
if (!isoutput && !isinput) {
free(name);
continue;
}
prev = NULL;
for (dev = unseen; dev; dev = next) {
next = dev->next;
if ( (SDL_strcmp(dev->name, name) == 0) && (((isinput) && dev->iscapture) || ((isoutput) && !dev->iscapture)) ) {
if (prev) {
prev->next = next;
} else {
unseen = next;
}
dev->next = seen;
seen = dev;
if (isinput) have_input = SDL_TRUE;
if (isoutput) have_output = SDL_TRUE;
} else {
prev = dev;
}
}
if (isinput && !have_input) {
add_device(SDL_TRUE, name, hints[i], &seen);
}
if (isoutput && !have_output) {
add_device(SDL_FALSE, name, hints[i], &seen);
}
}
free(name);
}
ALSA_snd_device_name_free_hint(hints);
devices = seen; /* now we have a known-good list of attached devices. */
/* report anything still in unseen as removed. */
for (dev = unseen; dev; dev = next) {
/*printf("ALSA: removing usb %s device '%s'\n", dev->iscapture ? "capture" : "output", dev->name);*/
next = dev->next;
SDL_RemoveAudioDevice(dev->iscapture, dev->name);
SDL_free(dev->name);
SDL_free(dev);
}
}
/* On first run, tell ALSA_DetectDevices() that we have a complete device list so it can return. */
if (first_run_semaphore) {
SDL_SemPost(first_run_semaphore);
first_run_semaphore = NULL; /* let other thread clean it up. */
}
/* Block awhile before checking again, unless we're told to stop. */
ticks = SDL_GetTicks() + 5000;
while (!SDL_AtomicGet(&ALSA_hotplug_shutdown) && !SDL_TICKS_PASSED(SDL_GetTicks(), ticks)) {
SDL_Delay(100);
}
}
/* Shutting down! Clean up any data we've gathered. */
for (dev = devices; dev; dev = next) {
/*printf("ALSA: at shutdown, removing %s device '%s'\n", dev->iscapture ? "capture" : "output", dev->name);*/
next = dev->next;
SDL_free(dev->name);
SDL_free(dev);
}
return 0;
}
static void
ALSA_DetectDevices(void)
{
/* Start the device detection thread here, wait for an initial iteration to complete. */
SDL_sem *semaphore = SDL_CreateSemaphore(0);
if (!semaphore) {
return; /* oh well. */
}
SDL_AtomicSet(&ALSA_hotplug_shutdown, 0);
ALSA_hotplug_thread = SDL_CreateThread(ALSA_HotplugThread, "SDLHotplugALSA", semaphore);
if (ALSA_hotplug_thread) {
SDL_SemWait(semaphore); /* wait for the first iteration to finish. */
}
SDL_DestroySemaphore(semaphore);
}
static void
ALSA_Deinitialize(void)
{
if (ALSA_hotplug_thread != NULL) {
SDL_AtomicSet(&ALSA_hotplug_shutdown, 1);
SDL_WaitThread(ALSA_hotplug_thread, NULL);
ALSA_hotplug_thread = NULL;
}
UnloadALSALibrary();
}
static int
ALSA_Init(SDL_AudioDriverImpl * impl)
{
if (LoadALSALibrary() < 0) {
return 0;
}
/* Set the function pointers */
impl->DetectDevices = ALSA_DetectDevices;
impl->OpenDevice = ALSA_OpenDevice;
impl->WaitDevice = ALSA_WaitDevice;
impl->GetDeviceBuf = ALSA_GetDeviceBuf;
impl->PlayDevice = ALSA_PlayDevice;
impl->CloseDevice = ALSA_CloseDevice;
impl->Deinitialize = ALSA_Deinitialize;
impl->CaptureFromDevice = ALSA_CaptureFromDevice;
impl->FlushCapture = ALSA_FlushCapture;
impl->HasCaptureSupport = SDL_TRUE;
return 1; /* this audio target is available. */
}
AudioBootStrap ALSA_bootstrap = {
"alsa", "ALSA PCM audio", ALSA_Init, 0
};
#endif /* SDL_AUDIO_DRIVER_ALSA */
/* vi: set ts=4 sw=4 expandtab: */
SDL_FirstAudioFormat
SDL_AudioFormat SDL_FirstAudioFormat(SDL_AudioFormat format)
Definition: SDL_audio.c:1584
AUDIO_S32MSB
#define AUDIO_S32MSB
Definition: SDL_audio.h:104
SDL_TRUE
Definition: SDL_stdinc.h:142
SDL_AudioDriverImpl::DetectDevices
void(* DetectDevices)(void)
Definition: SDL_sysaudio.h:67
AUDIO_U16LSB
#define AUDIO_U16LSB
Definition: SDL_audio.h:91
ticks
static int ticks
Definition: testtimer.c:24
SDL_atomic_t
A type representing an atomic integer value. It is a struct so people don&#39;t accidentally use numeric ...
Definition: SDL_atomic.h:198
SDL_CreateSemaphore
#define SDL_CreateSemaphore
Definition: SDL_dynapi_overrides.h:264
SDL_FALSE
Definition: SDL_stdinc.h:141
free
SDL_EventEntry * free
Definition: SDL_events.c:84
SDL_AudioDriverImpl::HasCaptureSupport
int HasCaptureSupport
Definition: SDL_sysaudio.h:91
SDL_AudioDriverImpl::PlayDevice
void(* PlayDevice)(_THIS)
Definition: SDL_sysaudio.h:73
SDL_AudioSpec::samples
Uint16 samples
Definition: SDL_audio.h:183
SDL_AudioDriverImpl::WaitDevice
void(* WaitDevice)(_THIS)
Definition: SDL_sysaudio.h:72
SDL_alsa_audio.h
SDL_OpenedAudioDeviceDisconnected
void SDL_OpenedAudioDeviceDisconnected(SDL_AudioDevice *device)
Definition: SDL_audio.c:449
SDL_AudioFormat
Uint16 SDL_AudioFormat
Audio format flags.
Definition: SDL_audio.h:64
Uint32
uint32_t Uint32
Definition: SDL_stdinc.h:181
SDL_LoadObject
#define SDL_LoadObject
Definition: SDL_dynapi_overrides.h:232
SDL_UnloadObject
#define SDL_UnloadObject
Definition: SDL_dynapi_overrides.h:234
SDL_zerop
#define SDL_zerop(x)
Definition: SDL_stdinc.h:417
SDL_strncmp
#define SDL_strncmp
Definition: SDL_dynapi_overrides.h:418
SDL_PrivateAudioData
Definition: SDL_alsa_audio.h:33
Uint64
uint64_t Uint64
Definition: SDL_stdinc.h:194
SDL_NextAudioFormat
SDL_AudioFormat SDL_NextAudioFormat(void)
Definition: SDL_audio.c:1596
bufsize
GLenum GLuint GLsizei bufsize
Definition: SDL_opengl_glext.h:1762
name
GLuint const GLchar * name
Definition: SDL_opengl_glext.h:660
SDL_SemPost
#define SDL_SemPost
Definition: SDL_dynapi_overrides.h:269
AUDIO_F32MSB
#define AUDIO_F32MSB
Definition: SDL_audio.h:113
format
GLint GLint GLsizei GLsizei GLsizei GLint GLenum format
Definition: SDL_opengl.h:1572
spec
SDL_AudioSpec spec
Definition: loopwave.c:31
device
static SDL_AudioDeviceID device
Definition: loopwave.c:37
size_t
unsigned int size_t
Definition: SDL_config_windows.h:68
retval
SDL_bool retval
Definition: testgamecontroller.c:65
AUDIO_U8
#define AUDIO_U8
Definition: SDL_audio.h:89
AudioBootStrap
Definition: SDL_sysaudio.h:175
SDL_AudioSpec::freq
int freq
Definition: SDL_audio.h:179
handle
EGLImageKHR EGLint EGLint * handle
Definition: eglext.h:937
SDL_GetTicks
Uint32 SDL_GetTicks(void)
Get the number of milliseconds since the SDL library initialization.
SDL_RemoveAudioDevice
void SDL_RemoveAudioDevice(const int iscapture, void *handle)
Definition: SDL_audio.c:490
SDL_AudioSpec::channels
Uint8 channels
Definition: SDL_audio.h:181
_THIS
#define _THIS
Definition: SDL_alsa_audio.h:31
Uint8
uint8_t Uint8
Definition: SDL_stdinc.h:157
SDL_free
#define SDL_free
Definition: SDL_dynapi_overrides.h:377
addr
GLenum const void * addr
Definition: SDL_opengl_glext.h:7945
SDL_AUDIO_BITSIZE
#define SDL_AUDIO_BITSIZE(x)
Definition: SDL_audio.h:75
AUDIO_F32LSB
#define AUDIO_F32LSB
Definition: SDL_audio.h:112
SDL_AudioDriverImpl
Definition: SDL_sysaudio.h:65
j
return Display return Display Bool Bool int int int return Display XEvent Bool(*) XPointer return Display return Display Drawable _Xconst char unsigned int unsigned int return Display Pixmap Pixmap XColor XColor unsigned int unsigned int return Display _Xconst char char int char return Display Visual unsigned int int int char unsigned int unsigned int int in j)
Definition: SDL_x11sym.h:50
SDL_AudioDriverImpl::Deinitialize
void(* Deinitialize)(void)
Definition: SDL_sysaudio.h:83
AUDIO_S32LSB
#define AUDIO_S32LSB
Definition: SDL_audio.h:103
SDL_CalculateAudioSpec
void SDL_CalculateAudioSpec(SDL_AudioSpec *spec)
Definition: SDL_audio.c:1605
buf
GLenum GLuint GLenum GLsizei const GLchar * buf
Definition: SDL_opengl_glext.h:2480
SDL_THREAD_PRIORITY_LOW
Definition: SDL_thread.h:60
SDL_atoi
#define SDL_atoi
Definition: SDL_dynapi_overrides.h:410
SDL_CreateThread
#define SDL_CreateThread
Definition: SDL_dynapi_overrides.h:41
SDL_Delay
#define SDL_Delay
Definition: SDL_dynapi_overrides.h:486
enabled
GLenum GLenum GLsizei const GLuint GLboolean enabled
Definition: SDL_opengl_glext.h:2479
SDL_getenv
#define SDL_getenv
Definition: SDL_dynapi_overrides.h:378
i
return Display return Display Bool Bool int int int return Display XEvent Bool(*) XPointer return Display return Display Drawable _Xconst char unsigned int unsigned int return Display Pixmap Pixmap XColor XColor unsigned int unsigned int return Display _Xconst char char int char return Display Visual unsigned int int int char unsigned int unsigned int in i)
Definition: SDL_x11sym.h:50
SDL_AudioSpec::size
Uint32 size
Definition: SDL_audio.h:185
ALSA_bootstrap
AudioBootStrap ALSA_bootstrap
SDL_assert
#define SDL_assert(condition)
Definition: SDL_assert.h:169
SDL_AudioDriverImpl::OpenDevice
int(* OpenDevice)(_THIS, void *handle, const char *devname, int iscapture)
Definition: SDL_sysaudio.h:68
NULL
#define NULL
Definition: begin_code.h:164
SDL_OutOfMemory
#define SDL_OutOfMemory()
Definition: SDL_error.h:52
SDL_bool
SDL_bool
Definition: SDL_stdinc.h:139
buffer
GLuint buffer
Definition: SDL_opengl_glext.h:533
SDL_AudioDriverImpl::CaptureFromDevice
int(* CaptureFromDevice)(_THIS, void *buffer, int buflen)
Definition: SDL_sysaudio.h:76
SDL_SetError
#define SDL_SetError
Definition: SDL_dynapi_overrides.h:30
SDL_loadso.h
SDL_AudioDriverImpl::CloseDevice
void(* CloseDevice)(_THIS)
Definition: SDL_sysaudio.h:79
AUDIO_S16MSB
#define AUDIO_S16MSB
Definition: SDL_audio.h:94
SDL_audio.h
SDL_strlen
#define SDL_strlen
Definition: SDL_dynapi_overrides.h:393
SDL_strdup
#define SDL_strdup
Definition: SDL_dynapi_overrides.h:397
SDL_AudioSpec::format
SDL_AudioFormat format
Definition: SDL_audio.h:180
SDL_AudioDriverImpl::FlushCapture
void(* FlushCapture)(_THIS)
Definition: SDL_sysaudio.h:77
void
SDL_PRINTF_FORMAT_STRING const char int SDL_PRINTF_FORMAT_STRING const char int SDL_PRINTF_FORMAT_STRING const char int SDL_PRINTF_FORMAT_STRING const char const char SDL_SCANF_FORMAT_STRING const char return SDL_ThreadFunction const char void return Uint32 return Uint32 void
Definition: SDL_dynapi_procs.h:89
SDL_SemWait
#define SDL_SemWait
Definition: SDL_dynapi_overrides.h:266
SDL_DestroySemaphore
#define SDL_DestroySemaphore
Definition: SDL_dynapi_overrides.h:265
AUDIO_S16LSB
#define AUDIO_S16LSB
Definition: SDL_audio.h:92
SDL_PrivateAudioData::pcm_handle
snd_pcm_t * pcm_handle
Definition: SDL_alsa_audio.h:36
SDL_AudioDriverImpl::GetDeviceBuf
Uint8 *(* GetDeviceBuf)(_THIS)
Definition: SDL_sysaudio.h:75
SDL_AtomicSet
#define SDL_AtomicSet
Definition: SDL_dynapi_overrides.h:67
params
const GLfloat * params
Definition: SDL_opengl_glext.h:371
SDL_AtomicGet
#define SDL_AtomicGet
Definition: SDL_dynapi_overrides.h:68
Uint16
uint16_t Uint16
Definition: SDL_stdinc.h:169
SDL_Thread
Definition: SDL_thread_c.h:54
SDL_malloc
#define SDL_malloc
Definition: SDL_dynapi_overrides.h:374
SDL_strcmp
#define SDL_strcmp
Definition: SDL_dynapi_overrides.h:417
SDL_LoadFunction
void * SDL_LoadFunction(void *handle, const char *name)
map
const GLubyte GLuint GLuint GLuint GLuint alpha GLboolean GLboolean GLboolean GLboolean alpha GLint GLint GLsizei GLsizei GLenum type GLenum GLint GLenum GLint GLint GLsizei GLsizei GLint border GLenum GLint GLint GLint GLint GLint GLsizei GLsizei height GLsizei GLsizei GLenum GLenum const GLvoid *pixels GLenum GLint GLint GLint GLint j2 GLdouble GLdouble GLdouble GLdouble GLdouble GLdouble zFar GLenum GLenum GLint *params GLenum GLenum GLint *params GLenum GLenum GLint *params GLenum GLenum GLfloat *params GLenum GLint GLenum GLenum GLvoid *pixels GLenum GLint GLenum GLint *params GLenum GLenum GLint *params GLenum GLsizei const GLvoid *pointer GLenum GLenum const GLint *params GLenum GLfloat GLfloat GLint GLint const GLfloat *points GLenum GLfloat GLfloat GLint GLint GLfloat GLfloat GLint GLint const GLfloat *points GLint GLfloat GLfloat GLint GLfloat GLfloat v2 GLenum GLenum const GLint *params GLdouble GLdouble GLdouble GLdouble GLdouble GLdouble zFar GLenum map
Definition: SDL_glfuncs.h:290
SDL_timer.h
SDL_TICKS_PASSED
#define SDL_TICKS_PASSED(A, B)
Compare SDL ticks values, and return true if A has passed B.
Definition: SDL_timer.h:56
AUDIO_S8
#define AUDIO_S8
Definition: SDL_audio.h:90
SDLCALL
#define SDLCALL
Definition: SDL_internal.h:45
devices
EGLDeviceEXT * devices
Definition: eglext.h:621
get_audio_device
static SDL_AudioDevice * get_audio_device(SDL_AudioDeviceID id)
Definition: SDL_audio.c:197
SDL_SetThreadPriority
#define SDL_SetThreadPriority
Definition: SDL_dynapi_overrides.h:477
SDL_memset
#define SDL_memset
Definition: SDL_dynapi_overrides.h:386
SDL_assert.h
SDL_WaitThread
#define SDL_WaitThread
Definition: SDL_dynapi_overrides.h:478
AUDIO_U16MSB
#define AUDIO_U16MSB
Definition: SDL_audio.h:93
SDL_AddAudioDevice
void SDL_AddAudioDevice(const int iscapture, const char *name, void *handle)
Definition: SDL_audio.c:432