[PATCH BlueZ v1 06/10] shared/mcp: Don't drop commands before supported opcodes are read

[Luiz Augusto von Dentz <luiz.dentz@gmail.com>]

From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

The remote player is created once the CCID of the service is read,
before Media Control Point Opcodes Supported is, and until then every
command was dropped. As the player returned the request id as error
code, the D-Bus call succeeded anyway, so e.g. a Play right after the
player appeared was silently lost.

Only refuse opcodes once the supported ones are known, letting the
server reject them otherwise, and report commands that were not sent as
errors.

Fixes: 9027edc4604e ("shared/mcp, mcp: support multiple MCP, and add non-stub MCS server")
Assisted-by: Claude:claude-opus-5-5
---
 profiles/audio/mcp.c | 10 +++++-----
 src/shared/mcp.c     |  8 +++++++-
 2 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/profiles/audio/mcp.c b/profiles/audio/mcp.c
index 314bce2439df..7522ca4e6ea3 100644
--- a/profiles/audio/mcp.c
+++ b/profiles/audio/mcp.c
@@ -253,35 +253,35 @@ static int remote_mp_play(struct media_player *mp, void *user_data)
 {
 	struct remote_player *remote = user_data;
 
-	return bt_mcp_play(remote->mcp, remote->ccid);
+	return bt_mcp_play(remote->mcp, remote->ccid) ? 0 : -EIO;
 }
 
 static int remote_mp_pause(struct media_player *mp, void *user_data)
 {
 	struct remote_player *remote = user_data;
 
-	return bt_mcp_pause(remote->mcp, remote->ccid);
+	return bt_mcp_pause(remote->mcp, remote->ccid) ? 0 : -EIO;
 }
 
 static int remote_mp_stop(struct media_player *mp, void *user_data)
 {
 	struct remote_player *remote = user_data;
 
-	return bt_mcp_stop(remote->mcp, remote->ccid);
+	return bt_mcp_stop(remote->mcp, remote->ccid) ? 0 : -EIO;
 }
 
 static int remote_mp_next(struct media_player *mp, void *user_data)
 {
 	struct remote_player *remote = user_data;
 
-	return bt_mcp_next_track(remote->mcp, remote->ccid);
+	return bt_mcp_next_track(remote->mcp, remote->ccid) ? 0 : -EIO;
 }
 
 static int remote_mp_previous(struct media_player *mp, void *user_data)
 {
 	struct remote_player *remote = user_data;
 
-	return bt_mcp_previous_track(remote->mcp, remote->ccid);
+	return bt_mcp_previous_track(remote->mcp, remote->ccid) ? 0 : -EIO;
 }
 
 static bool remote_mp_set_setting(struct media_player *mp, const char *key,
diff --git a/src/shared/mcp.c b/src/shared/mcp.c
index 4ee14d1567fe..8ddc072dacaa 100644
--- a/src/shared/mcp.c
+++ b/src/shared/mcp.c
@@ -108,6 +108,7 @@ struct bt_mcp_service {
 	struct bt_mcs_db rdb;
 
 	bool ready;
+	bool op_supported_known;
 
 	unsigned int notify_id[MAX_ATTR];
 	unsigned int notify_id_count;
@@ -1256,7 +1257,11 @@ static unsigned int mcp_command(struct bt_mcp *mcp, uint8_t ccid, uint8_t op,
 	if (!service || !cmd)
 		return 0;
 
-	if (!(service->rdb.media_cp_op_supported_value & cmd->support))
+	/* The service is added once its CCID is read, so commands may come
+	 * before the supported opcodes are known: let the server reject them
+	 */
+	if (service->op_supported_known &&
+		!(service->rdb.media_cp_op_supported_value & cmd->support))
 		return 0;
 
 	DBG_SVC(service, "%s %d", cmd->name, arg);
@@ -1686,6 +1691,7 @@ static void update_media_cp_op_supported(bool success, uint8_t att_ecode,
 	DBG_SVC(service, "Media CP Op Supported: %d", v);
 
 	service->rdb.media_cp_op_supported_value = v;
+	service->op_supported_known = true;
 }
 
 static void update_add_service(void *data, void *user_data)
-- 
2.56.0