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make SDL-1.2 to work with alsa-lib < 1.0.11 again

(drop snd_pcm_recover() dependency added by commit df306a61a)
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sezero committed Aug 15, 2019
1 parent 3c0d7b1 commit bd23a9ff36b72d71cfd5034d423446b7c620e7d5
Showing with 26 additions and 11 deletions.
  1. +1 −1 configure
  2. +1 −1 configure.in
  3. +24 −9 src/audio/alsa/SDL_alsa_audio.c
{ $as_echo "$as_me:$LINENO: result: $ALSA_LIBS" >&5
$as_echo "$ALSA_LIBS" >&6; }

min_alsa_version=1.0.11
min_alsa_version=0.9.0
{ $as_echo "$as_me:$LINENO: checking for libasound headers version >= $min_alsa_version" >&5
$as_echo_n "checking for libasound headers version >= $min_alsa_version... " >&6; }
no_alsa=""
@@ -361,7 +361,7 @@ CheckALSA()
AC_HELP_STRING([--enable-alsa], [support the ALSA audio API [[default=yes]]]),
, enable_alsa=yes)
if test x$enable_audio = xyes -a x$enable_alsa = xyes; then
AM_PATH_ALSA(1.0.11, have_alsa=yes, have_alsa=no)
AM_PATH_ALSA(0.9.0, have_alsa=yes, have_alsa=no)
# Restore all flags from before the ALSA detection runs
CFLAGS="$alsa_save_CFLAGS"
LDFLAGS="$alsa_save_LDFLAGS"
@@ -59,7 +59,7 @@ static int alsa_loaded = 0;
static int (*SDL_NAME(snd_pcm_open))(snd_pcm_t **pcm, const char *name, snd_pcm_stream_t stream, int mode);
static int (*SDL_NAME(snd_pcm_close))(snd_pcm_t *pcm);
static snd_pcm_sframes_t (*SDL_NAME(snd_pcm_writei))(snd_pcm_t *pcm, const void *buffer, snd_pcm_uframes_t size);
static int (*SDL_NAME(snd_pcm_recover))(snd_pcm_t *pcm, int err, int silent);
static int (*SDL_NAME(snd_pcm_resume))(snd_pcm_t *pcm);
static int (*SDL_NAME(snd_pcm_prepare))(snd_pcm_t *pcm);
static int (*SDL_NAME(snd_pcm_drain))(snd_pcm_t *pcm);
static const char *(*SDL_NAME(snd_strerror))(int errnum);
@@ -86,10 +86,10 @@ static int (*SDL_NAME(snd_pcm_sw_params_current))(snd_pcm_t *pcm, snd_pcm_sw_par
static int (*SDL_NAME(snd_pcm_sw_params_set_start_threshold))(snd_pcm_t *pcm, snd_pcm_sw_params_t *params, snd_pcm_uframes_t val);
static int (*SDL_NAME(snd_pcm_sw_params))(snd_pcm_t *pcm, snd_pcm_sw_params_t *params);
static int (*SDL_NAME(snd_pcm_nonblock))(snd_pcm_t *pcm, int nonblock);
static int (*SDL_NAME(snd_pcm_wait))(snd_pcm_t *pcm, int timeout);
#define snd_pcm_hw_params_sizeof SDL_NAME(snd_pcm_hw_params_sizeof)
#define snd_pcm_sw_params_sizeof SDL_NAME(snd_pcm_sw_params_sizeof)


/* cast funcs to char* first, to please GCC's strict aliasing rules. */
static struct {
const char *name;
@@ -98,7 +98,7 @@ static struct {
{ "snd_pcm_open", (void**)(char*)&SDL_NAME(snd_pcm_open) },
{ "snd_pcm_close", (void**)(char*)&SDL_NAME(snd_pcm_close) },
{ "snd_pcm_writei", (void**)(char*)&SDL_NAME(snd_pcm_writei) },
{ "snd_pcm_recover", (void**)(char*)&SDL_NAME(snd_pcm_recover) },
{ "snd_pcm_resume", (void**)(char*)&SDL_NAME(snd_pcm_resume) },
{ "snd_pcm_prepare", (void**)(char*)&SDL_NAME(snd_pcm_prepare) },
{ "snd_pcm_drain", (void**)(char*)&SDL_NAME(snd_pcm_drain) },
{ "snd_strerror", (void**)(char*)&SDL_NAME(snd_strerror) },
@@ -123,7 +123,6 @@ static struct {
{ "snd_pcm_sw_params_set_start_threshold", (void**)(char*)&SDL_NAME(snd_pcm_sw_params_set_start_threshold) },
{ "snd_pcm_sw_params", (void**)(char*)&SDL_NAME(snd_pcm_sw_params) },
{ "snd_pcm_nonblock", (void**)(char*)&SDL_NAME(snd_pcm_nonblock) },
{ "snd_pcm_wait", (void**)(char*)&SDL_NAME(snd_pcm_wait) },
};

static void UnloadALSALibrary(void) {
@@ -303,6 +302,25 @@ static __inline__ void swizzle_alsa_channels(_THIS)
}


/* snd_pcm_recover() is available in alsa-lib >= 1.0.11 */
static int ALSA_pcm_recover(snd_pcm_t *handle, int err, int silent)
{
(void) silent;
if (err == -EINTR) return 0;
if (err == -EPIPE) { /* under-run */
err = SDL_NAME(snd_pcm_prepare)(handle);
return (err < 0)? err : 0;
}
if (err == -ESTRPIPE) {
/* wait until suspend flag is released */
while ((err = SDL_NAME(snd_pcm_resume)(handle)) == -EAGAIN)
SDL_Delay(100);
if (err < 0) err = SDL_NAME(snd_pcm_prepare)(handle);
return (err < 0)? err : 0;
}
return err;
}

static void ALSA_PlayAudio(_THIS)
{
int status;
@@ -315,17 +333,14 @@ static void ALSA_PlayAudio(_THIS)
frames_left = ((snd_pcm_uframes_t) this->spec.samples);

while ( frames_left > 0 && this->enabled ) {
/* This works, but needs more testing before going live */
/*SDL_NAME(snd_pcm_wait)(pcm_handle, -1);*/

status = SDL_NAME(snd_pcm_writei)(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? */
/* Apparently snd_pcm_recover() doesn't handle this case. Foo. */
SDL_Delay(1);
continue;
}
status = SDL_NAME(snd_pcm_recover)(pcm_handle, status, 0);
status = ALSA_pcm_recover(pcm_handle, status, 0);
if ( status < 0 ) {
/* Hmm, not much we can do - abort */
fprintf(stderr, "ALSA write failed (unrecoverable): %s\n", SDL_NAME(snd_strerror)(status));

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