From 09ee977141f0ddc40697f04827cca61a1ef50809 Mon Sep 17 00:00:00 2001
From: Wim Taymans <wtaymans@redhat.com>
Date: Mon, 30 Aug 2021 17:36:11 +0200
Subject: [PATCH] alsa: cache UCM config

ALSA has problems with creating more than 8 configs per card so cache
the config per card and reuse it.

Fixes problems with no devices after logging out and in again because
ALSA can't create UCM profiles anymore.

See #1553
---
 spa/plugins/alsa/alsa-pcm.c | 110 +++++++++++++++++++++++++++---------
 spa/plugins/alsa/alsa-pcm.h |   2 +-
 2 files changed, 85 insertions(+), 27 deletions(-)

diff --git a/spa/plugins/alsa/alsa-pcm.c b/spa/plugins/alsa/alsa-pcm.c
index 825957bd3..b1b85a01d 100644
--- a/spa/plugins/alsa/alsa-pcm.c
+++ b/spa/plugins/alsa/alsa-pcm.c
@@ -16,10 +16,79 @@
 
 #include "alsa-pcm.h"
 
-int spa_alsa_init(struct state *state)
+static struct spa_list cards = SPA_LIST_INIT(&cards);
+
+struct card {
+	struct spa_list link;
+	int ref;
+	uint32_t index;
+	snd_use_case_mgr_t *ucm;
+};
+
+static struct card *find_card(uint32_t index)
 {
+	struct card *c;
+	spa_list_for_each(c, &cards, link) {
+		if (c->index == index) {
+			c->ref++;
+			return c;
+		}
+	}
+	return NULL;
+}
+
+static struct card *ensure_card(uint32_t index)
+{
+	struct card *c;
+	char card_name[64];
 	int err;
 
+	if ((c = find_card(index)) != NULL)
+		return c;
+
+	c = calloc(1, sizeof(*c));
+	c->ref = 1;
+	c->index = index;
+
+	snprintf(card_name, sizeof(card_name), "hw:%i", index);
+	err = snd_use_case_mgr_open(&c->ucm, card_name);
+	if (err < 0) {
+		char *name;
+		err = snd_card_get_name(index, &name);
+		if (err < 0) {
+			errno = -err;
+			return NULL;
+		}
+		snprintf(card_name, sizeof(card_name), "%s", name);
+		free(name);
+
+		err = snd_use_case_mgr_open(&c->ucm, card_name);
+		if (err < 0) {
+			errno = -err;
+			return NULL;
+		}
+	}
+	spa_list_append(&cards, &c->link);
+
+	return c;
+}
+
+static void release_card(uint32_t index)
+{
+	struct card *c;
+	if ((c = find_card(index)) == NULL)
+		return;
+
+	if (--c->ref > 0)
+		return;
+
+	snd_use_case_mgr_close(c->ucm);
+	spa_list_remove(&c->link);
+	free(c);
+}
+
+int spa_alsa_init(struct state *state)
+{
 	snd_config_update_free_global();
 
 	if (state->stream == SND_PCM_STREAM_PLAYBACK) {
@@ -28,49 +97,38 @@ int spa_alsa_init(struct state *state)
 	}
 
 	if (state->open_ucm) {
-		char card_name[64];
+		struct card *c;
 		const char *alibpref = NULL;
 
-		snprintf(card_name, sizeof(card_name), "hw:%i", state->card_index);
-		err = snd_use_case_mgr_open(&state->ucm, card_name);
-		if (err < 0) {
-			char *name;
-			err = snd_card_get_name(state->card_index, &name);
-			if (err < 0) {
-				spa_log_error(state->log,
-						"can't get card name from index %d",
-						state->card_index);
-				return err;
-			}
-			snprintf(card_name, sizeof(card_name), "%s", name);
-			free(name);
-
-			err = snd_use_case_mgr_open(&state->ucm, card_name);
-			if (err < 0) {
-				spa_log_error(state->log, "UCM not available for card %s", card_name);
-				return err;
-			}
+		c = ensure_card(state->card_index);
+		if (c == NULL) {
+			spa_log_error(state->log, "UCM not available for card %d", state->card_index);
+			return -errno;
 		}
 
-		if ((snd_use_case_get(state->ucm, "_alibpref", &alibpref) != 0))
+		if ((snd_use_case_get(c->ucm, "_alibpref", &alibpref) != 0))
 			alibpref = NULL;
 		if (alibpref != NULL) {
 			char name[sizeof(state->props.device)];
+			state->ucm_prefix_len = strlen(alibpref);
 			spa_scnprintf(name, sizeof(name), "%s%s", alibpref,
 					state->props.device);
 			strcpy(state->props.device, name);
 			free((void*)alibpref);
 		}
 	}
-
 	return 0;
 }
 
 int spa_alsa_clear(struct state *state)
 {
-	if (state->ucm)
-		snd_use_case_mgr_close(state->ucm);
-	state->ucm = NULL;
+	if (state->ucm_prefix_len > 0) {
+		memmove(state->props.device,
+				state->props.device + state->ucm_prefix_len,
+				sizeof(state->props.device) - state->ucm_prefix_len);
+		state->ucm_prefix_len = 0;
+	}
+	release_card(state->card_index);
 	return 0;
 }
 
diff --git a/spa/plugins/alsa/alsa-pcm.h b/spa/plugins/alsa/alsa-pcm.h
index 3ce3b0008..2dac2f1ab 100644
--- a/spa/plugins/alsa/alsa-pcm.h
+++ b/spa/plugins/alsa/alsa-pcm.h
@@ -205,7 +205,7 @@ struct state {
 	struct spa_latency_info latency[2];
 	struct spa_process_latency_info process_latency;
 
-	snd_use_case_mgr_t *ucm;
+	uint32_t ucm_prefix_len;
 };
 
 int