ALSA_snd_pcm_drop() can hang on some systems (Steam Link) so don't use that when shutting down the ALSA audio driver.

src/audio/alsa/SDL_alsa_audio.c

@@ -49,7 +49,6 @@ static snd_pcm_sframes_t (*ALSA_snd_pcm_readi)
 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 int (*ALSA_snd_pcm_drop) (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);
@@ -129,7 +128,6 @@ load_alsa_syms(void)
     SDL_ALSA_SYM(snd_pcm_recover);
     SDL_ALSA_SYM(snd_pcm_prepare);
     SDL_ALSA_SYM(snd_pcm_drain);
-    SDL_ALSA_SYM(snd_pcm_drop);
     SDL_ALSA_SYM(snd_strerror);
     SDL_ALSA_SYM(snd_pcm_hw_params_sizeof);
     SDL_ALSA_SYM(snd_pcm_sw_params_sizeof);
@@ -404,7 +402,12 @@ static void
 ALSA_CloseDevice(_THIS)
 {
     if (this->hidden->pcm_handle) {
-        ALSA_snd_pcm_drop(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);