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audio/sdlaudio: Remove the semaphore code
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The semaphore code was only working with SDL1.2 - with SDL2, it causes
a deadlock. Since we've removed support for SDL1.2 recently, we can
now completely remove the semaphore code from sdlaudio.c.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 1549336101-17623-2-git-send-email-thuth@redhat.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
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@huth @kraxel
huth authored and kraxel committed Feb 28, 2019
1 parent 7183834 commit 8a7816c
Showing 1 changed file with 5 additions and 140 deletions.
145 changes: 5 additions & 140 deletions audio/sdlaudio.c
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Expand Up @@ -38,14 +38,9 @@
#define AUDIO_CAP "sdl"
#include "audio_int.h"

#define USE_SEMAPHORE (SDL_MAJOR_VERSION < 2)

typedef struct SDLVoiceOut {
HWVoiceOut hw;
int live;
#if USE_SEMAPHORE
int rpos;
#endif
int decr;
} SDLVoiceOut;

Expand All @@ -57,10 +52,6 @@ static struct {

static struct SDLAudioState {
int exit;
#if USE_SEMAPHORE
SDL_mutex *mutex;
SDL_sem *sem;
#endif
int initialized;
bool driver_created;
} glob_sdl;
Expand All @@ -77,66 +68,6 @@ static void GCC_FMT_ATTR (1, 2) sdl_logerr (const char *fmt, ...)
AUD_log (AUDIO_CAP, "Reason: %s\n", SDL_GetError ());
}

static int sdl_lock (SDLAudioState *s, const char *forfn)
{
#if USE_SEMAPHORE
if (SDL_LockMutex (s->mutex)) {
sdl_logerr ("SDL_LockMutex for %s failed\n", forfn);
return -1;
}
#else
SDL_LockAudio();
#endif

return 0;
}

static int sdl_unlock (SDLAudioState *s, const char *forfn)
{
#if USE_SEMAPHORE
if (SDL_UnlockMutex (s->mutex)) {
sdl_logerr ("SDL_UnlockMutex for %s failed\n", forfn);
return -1;
}
#else
SDL_UnlockAudio();
#endif

return 0;
}

static int sdl_post (SDLAudioState *s, const char *forfn)
{
#if USE_SEMAPHORE
if (SDL_SemPost (s->sem)) {
sdl_logerr ("SDL_SemPost for %s failed\n", forfn);
return -1;
}
#endif

return 0;
}

#if USE_SEMAPHORE
static int sdl_wait (SDLAudioState *s, const char *forfn)
{
if (SDL_SemWait (s->sem)) {
sdl_logerr ("SDL_SemWait for %s failed\n", forfn);
return -1;
}
return 0;
}
#endif

static int sdl_unlock_and_post (SDLAudioState *s, const char *forfn)
{
if (sdl_unlock (s, forfn)) {
return -1;
}

return sdl_post (s, forfn);
}

static int aud_to_sdlfmt (audfmt_e fmt)
{
switch (fmt) {
Expand Down Expand Up @@ -243,9 +174,9 @@ static int sdl_open (SDL_AudioSpec *req, SDL_AudioSpec *obt)
static void sdl_close (SDLAudioState *s)
{
if (s->initialized) {
sdl_lock (s, "sdl_close");
SDL_LockAudio();
s->exit = 1;
sdl_unlock_and_post (s, "sdl_close");
SDL_UnlockAudio();
SDL_PauseAudio (1);
SDL_CloseAudio ();
s->initialized = 0;
Expand All @@ -267,30 +198,10 @@ static void sdl_callback (void *opaque, Uint8 *buf, int len)
int to_mix, decr;

/* dolog ("in callback samples=%d\n", samples); */
#if USE_SEMAPHORE
sdl_wait (s, "sdl_callback");
if (s->exit) {
return;
}

if (sdl_lock (s, "sdl_callback")) {
return;
}

if (audio_bug(__func__, sdl->live < 0 || sdl->live > hw->samples)) {
dolog ("sdl->live=%d hw->samples=%d\n",
sdl->live, hw->samples);
return;
}

if (!sdl->live) {
goto again;
}
#else
if (s->exit || !sdl->live) {
break;
}
#endif

/* dolog ("in callback live=%d\n", live); */
to_mix = audio_MIN (samples, sdl->live);
Expand All @@ -301,33 +212,20 @@ static void sdl_callback (void *opaque, Uint8 *buf, int len)

/* dolog ("in callback to_mix %d, chunk %d\n", to_mix, chunk); */
hw->clip (buf, src, chunk);
#if USE_SEMAPHORE
sdl->rpos = (sdl->rpos + chunk) % hw->samples;
#else
hw->rpos = (hw->rpos + chunk) % hw->samples;
#endif
to_mix -= chunk;
buf += chunk << hw->info.shift;
}
samples -= decr;
sdl->live -= decr;
sdl->decr += decr;

#if USE_SEMAPHORE
again:
if (sdl_unlock (s, "sdl_callback")) {
return;
}
#endif
}
/* dolog ("done len=%d\n", len); */

#if (SDL_MAJOR_VERSION >= 2)
/* SDL2 does not clear the remaining buffer for us, so do it on our own */
if (samples) {
memset(buf, 0, samples << hw->info.shift);
}
#endif
}

static int sdl_write_out (SWVoiceOut *sw, void *buf, int len)
Expand All @@ -339,11 +237,8 @@ static int sdl_run_out (HWVoiceOut *hw, int live)
{
int decr;
SDLVoiceOut *sdl = (SDLVoiceOut *) hw;
SDLAudioState *s = &glob_sdl;

if (sdl_lock (s, "sdl_run_out")) {
return 0;
}
SDL_LockAudio();

if (sdl->decr > live) {
ldebug ("sdl->decr %d live %d sdl->live %d\n",
Expand All @@ -355,19 +250,10 @@ static int sdl_run_out (HWVoiceOut *hw, int live)
decr = audio_MIN (sdl->decr, live);
sdl->decr -= decr;

#if USE_SEMAPHORE
sdl->live = live - decr;
hw->rpos = sdl->rpos;
#else
sdl->live = live;
#endif

if (sdl->live > 0) {
sdl_unlock_and_post (s, "sdl_run_out");
}
else {
sdl_unlock (s, "sdl_run_out");
}
SDL_UnlockAudio();

return decr;
}

Expand Down Expand Up @@ -449,23 +335,6 @@ static void *sdl_audio_init (void)
return NULL;
}

#if USE_SEMAPHORE
s->mutex = SDL_CreateMutex ();
if (!s->mutex) {
sdl_logerr ("Failed to create SDL mutex\n");
SDL_QuitSubSystem (SDL_INIT_AUDIO);
return NULL;
}

s->sem = SDL_CreateSemaphore (0);
if (!s->sem) {
sdl_logerr ("Failed to create SDL semaphore\n");
SDL_DestroyMutex (s->mutex);
SDL_QuitSubSystem (SDL_INIT_AUDIO);
return NULL;
}
#endif

s->driver_created = true;
return s;
}
Expand All @@ -474,10 +343,6 @@ static void sdl_audio_fini (void *opaque)
{
SDLAudioState *s = opaque;
sdl_close (s);
#if USE_SEMAPHORE
SDL_DestroySemaphore (s->sem);
SDL_DestroyMutex (s->mutex);
#endif
SDL_QuitSubSystem (SDL_INIT_AUDIO);
s->driver_created = false;
}
Expand Down

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