From 34691de22bb6014788447805367b490d2bfff4da Mon Sep 17 00:00:00 2001
From: vanfanel <[EMAIL REDACTED]>
Date: Sun, 20 Jul 2025 14:23:45 +0200
Subject: [PATCH] SDL2: Fill the SDL_AudioSpec in add_device()
---
src/audio/alsa/SDL_alsa_audio.c | 46 +++++++++++++++++++++++++++++----
1 file changed, 41 insertions(+), 5 deletions(-)
diff --git a/src/audio/alsa/SDL_alsa_audio.c b/src/audio/alsa/SDL_alsa_audio.c
index 8f3a49c81489b..457d7ce575e8b 100644
--- a/src/audio/alsa/SDL_alsa_audio.c
+++ b/src/audio/alsa/SDL_alsa_audio.c
@@ -62,6 +62,7 @@ static int (*ALSA_snd_pcm_hw_params_set_access)(snd_pcm_t *, snd_pcm_hw_params_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_get_rate)(snd_pcm_hw_params_t *, unsigned int*, 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 *);
@@ -138,6 +139,7 @@ static int load_alsa_syms(void)
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_get_rate);
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);
@@ -780,6 +782,16 @@ static void add_device(const int iscapture, const char *name, void *hint, ALSA_D
char *desc;
char *handle = NULL;
char *ptr;
+ snd_pcm_t *pcm_handle;
+ snd_pcm_stream_t stream;
+ snd_pcm_hw_params_t *hwparams;
+
+ unsigned int freq = 0;
+ int dir;
+ unsigned int channels = 0;
+ snd_pcm_uframes_t samples = 0;
+
+ SDL_AudioSpec spec;
if (!dev) {
return;
@@ -819,12 +831,36 @@ static void add_device(const int iscapture, const char *name, void *hint, ALSA_D
SDL_free(dev);
return;
}
+ stream = iscapture ? SND_PCM_STREAM_CAPTURE : SND_PCM_STREAM_PLAYBACK;
+
+ if (ALSA_snd_pcm_open(&pcm_handle, handle, stream, SND_PCM_NONBLOCK) < 0) {
+ SDL_free(dev);
+ return;
+ }
- /* Note that spec is NULL, because we are required to open the device before
- * acquiring the mix format, making this information inaccessible at
- * enumeration time
- */
- SDL_AddAudioDevice(iscapture, desc, NULL, handle);
+ snd_pcm_hw_params_alloca(&hwparams);
+ ALSA_snd_pcm_hw_params_any(pcm_handle, hwparams);
+
+ ALSA_snd_pcm_hw_params_get_rate(hwparams, &freq, &dir);
+ ALSA_snd_pcm_hw_params_get_channels(hwparams, &channels);
+ ALSA_snd_pcm_hw_params_get_period_size(hwparams, &samples, &dir);
+
+ ALSA_snd_pcm_close(pcm_handle);
+
+ /* Let's fill the spec */
+
+ spec.freq = freq;
+ spec.channels = channels;
+ spec.samples = samples;
+ spec.silence = 0;
+ spec.padding = 0;
+ /* Can't calculate size yet because this is an exploratory device opening
+ * so we don't know the sample format.
+ * Probably AUDIO_S16SYS/SND_PCM_FORMAT_S16_LE would be a good default
+ * if required.*/
+ spec.size = 0;
+
+ SDL_AddAudioDevice(iscapture, desc, &spec, handle);
if (hint) {
free(desc);
}