From 2f30c4986c5f564b206f4acee8bb9b1824b131df Mon Sep 17 00:00:00 2001
From: Michel Pollet <buserror@gmail.com>
Date: Sat, 28 Oct 2023 06:16:56 +0100
Subject: [PATCH] speaker: Allow disabling audio, not just muting

Allow turning off the audio output (ie not initialize it). Also removed
the debug file descriptor global

Signed-off-by: Michel Pollet <buserror@gmail.com>
---
 src/mii_speaker.c | 27 +++++++++++++++------------
 src/mii_speaker.h |  2 ++
 2 files changed, 17 insertions(+), 12 deletions(-)

diff --git a/src/mii_speaker.c b/src/mii_speaker.c
index 521b899..42f1287 100644
--- a/src/mii_speaker.c
+++ b/src/mii_speaker.c
@@ -90,7 +90,8 @@ mii_speaker_init(
 	s->mii = mii;
 	s->fsize = MII_SPEAKER_FRAME_SIZE;
 #ifdef HAS_ALSA
-	_alsa_init(s);	// this can/will change fsize
+	if (!s->off)
+		_alsa_init(s);	// this can/will change fsize
 #endif
 	s->vol_multiplier = 0.2;
 	s->sample = 0x8000;
@@ -132,7 +133,8 @@ mii_speaker_click(
 			(s->mii->cycles - f->start) > (2 * s->fsize * s->clk_per_sample)) {
 	//	printf("Restarting playback\n");
 #ifdef HAS_ALSA
-		snd_pcm_prepare(s->alsa_pcm);
+		if (s->alsa_pcm)
+			snd_pcm_prepare(s->alsa_pcm);
 #endif
 		f->start = s->mii->cycles - (s->clk_per_sample * 8);
 		f->fill = 0;
@@ -166,7 +168,6 @@ mii_speaker_click(
 	f->audio[sample_index] = s->sample * s->vol_multiplier;
 }
 
-int g_mii_audio_record_fd = -1;
 
 // Check to see if there's a new frame to send, send it
 void
@@ -186,15 +187,17 @@ mii_speaker_run(
 		s->fplay = (s->fplay + 1) % MII_SPEAKER_FRAME_COUNT;
 		f = &s->frame[s->fplaying];
 		if (!s->muted) {
-#ifdef HAS_ALSA
-			int pcm;
-			if (g_mii_audio_record_fd != -1)
-				write(g_mii_audio_record_fd, f->audio,
+			if (s->debug_fd != -1)
+				write(s->debug_fd, f->audio,
 							f->fill * sizeof(s->frame[0].audio[0]));
-			if ((pcm = snd_pcm_writei(s->alsa_pcm,
-						f->audio, f->fill)) == -EPIPE) {
-				printf("%s Underrun.\n", __func__);
-				snd_pcm_recover(s->alsa_pcm, pcm, 1);
+#ifdef HAS_ALSA
+			if (s->alsa_pcm) {
+				int pcm;
+				if ((pcm = snd_pcm_writei(s->alsa_pcm,
+							f->audio, f->fill)) == -EPIPE) {
+					printf("%s Underrun.\n", __func__);
+					snd_pcm_recover(s->alsa_pcm, pcm, 1);
+				}
 			}
 #endif
 		}
@@ -223,4 +226,4 @@ mii_speaker_volume(
 	s->volume = volume;
 
 //	printf("audio: speaker volume set to %.3f (%.4f)\n", volume, mul);
-}
\ No newline at end of file
+}
diff --git a/src/mii_speaker.h b/src/mii_speaker.h
index a8b1b42..a9995cc 100644
--- a/src/mii_speaker.h
+++ b/src/mii_speaker.h
@@ -24,8 +24,10 @@ typedef struct mii_audio_frame_t {
 
 typedef struct mii_speaker_t {
 	struct mii_t * mii;
+	int			debug_fd;		// if > 0, dump audio to this fd
 	void * 		alsa_pcm;		// alsa pcm handle
 	bool		muted;			// if true, don't play anything
+	bool		off;			// if true, don't even initialize (alsa)
 	float 		volume;			// volume, 0.0 to 10.0
 	float 		vol_multiplier;	// sample multiplier, 0.0 to 1.0
 	float 		cpu_speed;		// CPU speed in MHz, to calculate clk_per_sample