From 83b198215d9bbec8ba0db573e79a7f6cc3ede68b Mon Sep 17 00:00:00 2001
From: Wim Taymans <wtaymans@redhat.com>
Date: Tue, 22 Jun 2021 09:18:33 +0200
Subject: [PATCH] filter: use the user param_info field for updates

Keep track of the number of updates in the user field and before
emiting the info, flip the serial flag. This makes it possible to
even emit updates when setting an even number of params.
---
 src/pipewire/filter.c | 31 +++++++++++++++++++++++++++----
 1 file changed, 27 insertions(+), 4 deletions(-)

diff --git a/src/pipewire/filter.c b/src/pipewire/filter.c
index 746392604..cc412a183 100644
--- a/src/pipewire/filter.c
+++ b/src/pipewire/filter.c
@@ -241,13 +241,16 @@ static struct param *add_param(struct filter *impl, struct port *port,
 	memcpy(p->param, param, SPA_POD_SIZE(param));
 	SPA_POD_OBJECT_ID(p->param) = id;
 
+	pw_log_debug(NAME" %p: port %p param id %d (%s)", impl, p, id,
+			spa_debug_type_find_name(spa_type_param, id));
+
 	if (port) {
 		idx = get_port_param_index(id);
 		spa_list_append(&port->param_list, &p->link);
 		if (idx != -1) {
 			port->info.change_mask |= SPA_PORT_CHANGE_MASK_PARAMS;
 			port->params[idx].flags |= SPA_PARAM_INFO_READ;
-			port->params[idx].flags ^= SPA_PARAM_INFO_SERIAL;
+			port->params[idx].user++;
 		}
 	} else {
 		idx = get_param_index(id);
@@ -255,7 +258,7 @@ static struct param *add_param(struct filter *impl, struct port *port,
 		if (idx != -1) {
 			impl->info.change_mask |= SPA_NODE_CHANGE_MASK_PARAMS;
 			impl->params[idx].flags |= SPA_PARAM_INFO_READ;
-			impl->params[idx].flags ^= SPA_PARAM_INFO_SERIAL;
+			impl->params[idx].user++;
 		}
 	}
 	return p;
@@ -442,21 +445,41 @@ static int impl_send_command(void *object, const struct spa_command *command)
 
 static void emit_node_info(struct filter *d, bool full)
 {
+	uint32_t i;
 	uint64_t old = full ? d->info.change_mask : 0;
 	if (full)
 		d->info.change_mask = d->change_mask_all;
-	if (d->info.change_mask != 0)
+	if (d->info.change_mask != 0) {
+		if (d->info.change_mask & SPA_NODE_CHANGE_MASK_PARAMS) {
+			for (i = 0; i < d->info.n_params; i++) {
+				if (d->params[i].user > 0) {
+					d->params[i].flags ^= SPA_PARAM_INFO_SERIAL;
+					d->params[i].user = 0;
+				}
+			}
+		}
 		spa_node_emit_info(&d->hooks, &d->info);
+	}
 	d->info.change_mask = old;
 }
 
 static void emit_port_info(struct filter *d, struct port *p, bool full)
 {
+	uint32_t i;
 	uint64_t old = full ? p->info.change_mask : 0;
 	if (full)
 		p->info.change_mask = p->change_mask_all;
-	if (p->info.change_mask != 0)
+	if (p->info.change_mask != 0) {
+		if (p->info.change_mask & SPA_PORT_CHANGE_MASK_PARAMS) {
+			for (i = 0; i < p->info.n_params; i++) {
+				if (p->params[i].user > 0) {
+					p->params[i].flags ^= SPA_PARAM_INFO_SERIAL;
+					p->params[i].user = 0;
+				}
+			}
+		}
 		spa_node_emit_port_info(&d->hooks, p->direction, p->id, &p->info);
+	}
 	p->info.change_mask = old;
 }