From 1bf6dead10e016f4e33bb8fd0a70baaeaa162454 Mon Sep 17 00:00:00 2001
From: Wim Taymans <wtaymans@redhat.com>
Date: Wed, 16 Sep 2020 15:14:26 +0200
Subject: [PATCH] alsa: add option to force a samplerate

---
 spa/include/spa/param/audio/raw.h  | 1 +
 spa/plugins/alsa/alsa-pcm-sink.c   | 2 ++
 spa/plugins/alsa/alsa-pcm-source.c | 2 ++
 spa/plugins/alsa/alsa-pcm.c        | 7 +++++++
 spa/plugins/alsa/alsa-pcm.h        | 1 +
 5 files changed, 13 insertions(+)

diff --git a/spa/include/spa/param/audio/raw.h b/spa/include/spa/param/audio/raw.h
index 18debcce4..849a88c92 100644
--- a/spa/include/spa/param/audio/raw.h
+++ b/spa/include/spa/param/audio/raw.h
@@ -222,6 +222,7 @@ struct spa_audio_info_raw {
 #define SPA_KEY_AUDIO_CHANNEL		"audio.channel"		/**< an audio channel as string,
 								  *  Ex. "FL" */
 #define SPA_KEY_AUDIO_CHANNELS		"audio.channels"	/**< an audio channel count as int */
+#define SPA_KEY_AUDIO_RATE		"audio.rate"		/**< an audio sample rate as int */
 
 struct spa_audio_info_dsp {
 	enum spa_audio_format format;		/*< format, one of the DSP formats in enum spa_audio_format_dsp */
diff --git a/spa/plugins/alsa/alsa-pcm-sink.c b/spa/plugins/alsa/alsa-pcm-sink.c
index 6f0afaf3a..b35becba5 100644
--- a/spa/plugins/alsa/alsa-pcm-sink.c
+++ b/spa/plugins/alsa/alsa-pcm-sink.c
@@ -763,6 +763,8 @@ impl_init(const struct spa_handle_factory *factory,
 			snprintf(this->props.device, 63, "%s", info->items[i].value);
 		} else if (!strcmp(info->items[i].key, SPA_KEY_AUDIO_CHANNELS)) {
 			this->default_channels = atoi(info->items[i].value);
+		} else if (!strcmp(info->items[i].key, SPA_KEY_AUDIO_RATE)) {
+			this->default_rate = atoi(info->items[i].value);
 		}
 	}
 
diff --git a/spa/plugins/alsa/alsa-pcm-source.c b/spa/plugins/alsa/alsa-pcm-source.c
index 06077f642..0e0bf9b80 100644
--- a/spa/plugins/alsa/alsa-pcm-source.c
+++ b/spa/plugins/alsa/alsa-pcm-source.c
@@ -782,6 +782,8 @@ impl_init(const struct spa_handle_factory *factory,
 			snprintf(this->props.device, 63, "%s", info->items[i].value);
 		} else if (!strcmp(info->items[i].key, SPA_KEY_AUDIO_CHANNELS)) {
 			this->default_channels = atoi(info->items[i].value);
+		} else if (!strcmp(info->items[i].key, SPA_KEY_AUDIO_RATE)) {
+			this->default_rate = atoi(info->items[i].value);
 		}
 	}
 	return 0;
diff --git a/spa/plugins/alsa/alsa-pcm.c b/spa/plugins/alsa/alsa-pcm.c
index 78c4a3f7a..8c993700b 100644
--- a/spa/plugins/alsa/alsa-pcm.c
+++ b/spa/plugins/alsa/alsa-pcm.c
@@ -341,6 +341,13 @@ spa_alsa_enum_format(struct state *state, int seq, uint32_t start, uint32_t num,
 	CHECK(snd_pcm_hw_params_get_rate_min(params, &min, &dir), "get_rate_min");
 	CHECK(snd_pcm_hw_params_get_rate_max(params, &max, &dir), "get_rate_max");
 
+	if (state->default_rate != 0) {
+		if (min < state->default_rate)
+			min = state->default_rate;
+		if (max > state->default_rate)
+			max = state->default_rate;
+	}
+
 	spa_pod_builder_prop(&b, SPA_FORMAT_AUDIO_rate, 0);
 
 	spa_pod_builder_push_choice(&b, &f[1], SPA_CHOICE_None, 0);
diff --git a/spa/plugins/alsa/alsa-pcm.h b/spa/plugins/alsa/alsa-pcm.h
index 6f8499e25..463bb350c 100644
--- a/spa/plugins/alsa/alsa-pcm.h
+++ b/spa/plugins/alsa/alsa-pcm.h
@@ -104,6 +104,7 @@ struct state {
 	struct spa_audio_info current_format;
 
 	unsigned int default_channels;
+	unsigned int default_rate;
 
 	snd_pcm_uframes_t buffer_frames;
 	snd_pcm_uframes_t period_frames;