docs: add discovery flow diagrams, document restart detection limitation

- Four Mermaid sequence diagrams: startup, steady-state keepalive, node
  loss/timeout, and node restart
- Explicitly document that the site_id-change restart heuristic does not work
  in practice (site_id is static config, not a runtime value)
- Describe what needs to change: a boot nonce (random u32 at startup)
- Add boot nonce as a deferred item in planning.md

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

dev/cli/controller_cli.c

@@ -163,7 +163,7 @@ static void on_standalone(
 	(*idx)++;
 }
 
-static const char *scale_name(uint8_t s)
+static const char *scale_mode_name(uint8_t s)
 {
 	switch (s) {
 	case 0: return "stretch";
@@ -179,13 +179,13 @@ static void on_display(
 	uint16_t stream_id,
 	int16_t win_x, int16_t win_y,
 	uint16_t win_w, uint16_t win_h,
-	uint8_t scale, uint8_t anchor,
+	uint8_t scale_mode, uint8_t anchor,
 	void *ud)
 {
 	(void)ud;
-	printf("  [%u] display  stream=%u  pos=%d,%d  size=%ux%u  scale=%s  anchor=%s\n",
+	printf("  [%u] display  stream=%u  pos=%d,%d  size=%ux%u  scale_mode=%s  anchor=%s\n",
 		device_id, stream_id, win_x, win_y, win_w, win_h,
-		scale_name(scale),
+		scale_mode_name(scale_mode),
 		anchor == 0 ? "center" : "topleft");
 }
 

docs/cli/discovery_cli.md

@@ -1,6 +1,6 @@
 # discovery_cli
 
-A development tool for testing the UDP multicast discovery layer. Announces a node on the local network and prints peers as they appear and disappear.
+A development tool for testing the discovery layer. Announces a node on the local network via UDP multicast and prints peers as they appear and disappear.
 
 ---
 

docs/discovery.md

@@ -43,11 +43,81 @@ A node may set multiple bits — a relay that also archives sets both `RELAY` an
 
 ### Behaviour
 
-- Nodes send announcements periodically (e.g. every 5 s) and immediately on startup
+- Nodes send announcements periodically (default every 5 s) and immediately on startup via multicast
 - No daemon — the node process itself sends and listens; no background service required
-- On receiving an announcement, the control plane records the peer (address, port, name, function) and can initiate a transport connection if needed
+- On receiving an announcement the node records the peer (address, port, name, capabilities) and can initiate a transport connection if needed
-- A node going silent for a configured number of announcement intervals is considered offline
+- A peer that goes silent for `timeout_intervals × interval_ms` is considered offline and removed from the peer table
-- Announcements are informational only — the hub validates identity at connection time
+- Announcements are informational only — identity is validated at TCP connection time
+
+#### Startup — new node joins the network
+
+```mermaid
+sequenceDiagram
+    participant N as New Node
+    participant MC as Multicast group
+    participant A as Node A
+    participant B as Node B
+
+    N->>MC: announce (multicast)
+    MC-->>A: receives announce
+    MC-->>B: receives announce
+    A->>N: announce (unicast reply)
+    B->>N: announce (unicast reply)
+    Note over N,B: All parties now know each other.<br/>Subsequent keepalives are multicast only.
+```
+
+Each node that hears a new peer sends a **unicast reply** directly to that peer. This allows the new node to populate its peer table within one round-trip rather than waiting up to `interval_ms` for other nodes' next scheduled broadcast.
+
+#### Steady-state keepalive
+
+```mermaid
+sequenceDiagram
+    participant A as Node A
+    participant MC as Multicast group
+    participant B as Node B
+    participant C as Node C
+
+    loop every interval_ms
+        A->>MC: announce (multicast)
+        MC-->>B: receives — updates last_seen_ms, no reply
+        MC-->>C: receives — updates last_seen_ms, no reply
+    end
+```
+
+Known peers update their `last_seen_ms` timestamp and do nothing else. No reply is sent, so there is no amplification.
+
+#### Node loss — timeout
+
+```mermaid
+sequenceDiagram
+    participant A as Node A
+    participant B as Node B (offline)
+
+    Note over B: Node B stops sending
+    loop timeout_intervals × interval_ms elapses
+        A->>A: check_timeouts() — not yet expired
+    end
+    A->>A: check_timeouts() — expired, remove B
+    A->>A: on_peer_lost(B) callback
+```
+
+#### Node restart — known limitation
+
+The current implementation attempts to detect a restart by checking whether `site_id` changed for a known `(addr, port)` entry. In practice this **does not work**: `site_id` is a static configuration value and will be the same before and after a restart. A restarted node will therefore simply be treated as a continuing keepalive and will not receive an immediate unicast reply — it will have to wait up to `interval_ms` for the next scheduled multicast broadcast from its peers.
+
+```mermaid
+sequenceDiagram
+    participant R as Restarted Node
+    participant MC as Multicast group
+    participant A as Node A
+
+    Note over R: Node restarts — same addr, port, site_id
+    R->>MC: announce (multicast)
+    MC-->>A: receives — site_id unchanged, treated as keepalive
+    Note over A: No unicast reply sent. R waits up to interval_ms<br/>to learn about A via A's next scheduled multicast.
+```
+
+**What needs to change:** a **boot nonce** (random `u32` generated at startup, not configured) should be added to the announcement payload. A change in boot nonce for a known peer unambiguously signals a restart and triggers an immediate unicast reply. This requires a wire format version bump and updates to the peer table struct, announcement builder, and receive logic.
 
 ### No Avahi/Bonjour Dependency
 

include/protocol.h

@@ -157,7 +157,7 @@ struct Proto_Display_Device_Info {
 	uint16_t stream_id;
 	int16_t  win_x, win_y;
 	uint16_t win_w, win_h;
-	uint8_t  scale;
+	uint8_t  scale_mode;
 	uint8_t  anchor;
 };
 
@@ -166,7 +166,7 @@ struct Proto_Display_Device_Info {
  * SET_CONTROL for display device indices returned by ENUM_DEVICES.
  * ------------------------------------------------------------------------- */
 
-#define PROTO_DISPLAY_CTRL_SCALE            0x00D00001u  /* int 0-3: stretch/fit/fill/1:1 */
+#define PROTO_DISPLAY_CTRL_SCALE_MODE       0x00D00001u  /* int 0-3: stretch/fit/fill/1:1 */
 #define PROTO_DISPLAY_CTRL_ANCHOR           0x00D00002u  /* int 0-1: center/topleft */
 #define PROTO_DISPLAY_CTRL_NO_SIGNAL_FPS    0x00D00003u  /* int 1-60: no-signal animation fps */
 
@@ -262,7 +262,7 @@ struct Proto_Stop_Ingest {
  * display incoming VIDEO_FRAME messages for the given stream_id.
  * win_x/win_y are screen-space window position (signed: multi-monitor).
  * win_w/win_h of 0 mean use a default size.
- * scale: 0=stretch 1=fit 2=fill 3=1:1 (PROTO_DISPLAY_SCALE_*)
+ * scale_mode: 0=stretch 1=fit 2=fill 3=1:1 (PROTO_DISPLAY_SCALE_*)
  * anchor: 0=center 1=topleft (PROTO_DISPLAY_ANCHOR_*)
  */
 struct Proto_Start_Display {
@@ -272,7 +272,7 @@ struct Proto_Start_Display {
 	int16_t  win_y;
 	uint16_t win_w;
 	uint16_t win_h;
-	uint8_t  scale;
+	uint8_t  scale_mode;
 	uint8_t  anchor;
 	uint8_t  no_signal_fps;  /* 0 = default (15); no-signal animation frame rate */
 	/* 1 byte reserved */
@@ -365,7 +365,7 @@ struct App_Error proto_write_stop_ingest(struct Transport_Conn *conn,
 struct App_Error proto_write_start_display(struct Transport_Conn *conn,
 	uint16_t request_id, uint16_t stream_id,
 	int16_t win_x, int16_t win_y, uint16_t win_w, uint16_t win_h,
-	uint8_t scale, uint8_t anchor, uint8_t no_signal_fps);
+	uint8_t scale_mode, uint8_t anchor, uint8_t no_signal_fps);
 
 /* CONTROL_REQUEST: STOP_DISPLAY */
 struct App_Error proto_write_stop_display(struct Transport_Conn *conn,
@@ -510,7 +510,7 @@ struct App_Error proto_read_enum_devices_response(
 		uint16_t stream_id,
 		int16_t  win_x,  int16_t  win_y,
 		uint16_t win_w,  uint16_t win_h,
-		uint8_t  scale,  uint8_t  anchor,
+		uint8_t  scale_mode, uint8_t anchor,
 		void *userdata),
 	void *userdata);
 

planning.md

@@ -132,6 +132,9 @@ These are open questions tracked in `architecture.md` that do not need to be res
 - Hard vs soft byte budget limits
 - Cooperative capture release: if a capture source has no live downstream targets for a configurable time window, stop capture and release the device. Intended as a resource-conservation policy rather than an immediate reaction to disconnect events. Requires the node to track downstream liveness (e.g. last successful send timestamp per output) and implement a reaper timer.
 - Unified device model: active display windows should be registered as devices alongside V4L2 cameras, using the same ENUM_DEVICES / ENUM_CONTROLS / GET_CONTROL / SET_CONTROL protocol. START_DISPLAY would return a device_id for the opened window; controls (scale, anchor, position, size, zoom, pan) are then addressable as (device_id, control_id) pairs like any other device. Requires a device_type field in ENUM_DEVICES responses so controllers can distinguish V4L2 devices from display windows. Future device types: codec processes, screen grab sources. This extends naturally to shader-based post-processing and other viewer state as controls.
+- Display viewer free pan/zoom mode: the current anchor system (center/topleft) only covers fixed alignment. A "free" mode should allow the controller (or the user via mouse/keyboard in the window) to set arbitrary pan offset and zoom level independently of the scale mode. The xorg viewer would need pan_x/pan_y (normalised or pixel offsets) and zoom_factor controls alongside the existing scale/anchor. This is a prerequisite for use cases like microscope inspection where the user needs to freely navigate a high-resolution source.
 - controller_cli is a temporary dev tool; the long-term replacement is a dedicated `controller` binary outside `dev/cli/` that maintains simultaneous connections to all discovered nodes (not switching between them). Commands address a specific node by peer index. This mirrors the web UI's model of administering the whole network rather than one node at a time. The `connect` / active-connection model in the current controller_cli is an interim design choice that should not be carried forward.
 - start-ingest peer addressing: the `dest_host` + `dest_port` in START_INGEST is awkward to type manually and requires the caller to know the target's TCP port. Should accept a peer ID (index from the discovered peer table on the node) so the node can resolve the address itself. Requires the node to run discovery and expose its peer table.
 - Connection multiplexing: currently each ingest stream opens its own outbound TCP connection to the destination. Multiple streams between the same two peers should share one connection, with stream_id used to demultiplex frames. This is the priority/encapsulation scheme described in the architecture — high-priority and low-latency frames from different streams travel over the same socket rather than competing across separate sockets.
+- Discovery boot nonce: the announcement payload needs a `boot_nonce` field (random u32 generated at startup, not configured). The current restart detection uses `site_id` change as a proxy, but `site_id` is static config and does not change on restart, so restarts are not detected and the restarted node waits up to `interval_ms` for peers to reply. Adding a boot nonce gives a reliable restart signal: a nonce change for a known (addr, port) entry triggers an immediate unicast reply. Requires a wire format version bump, peer table struct update, and changes to the announcement builder and receive logic.
+- Control grouping: controls should be organizable into named groups for both display organisation (collapsible sections in a UI) and protocol semantics (enumerate controls within a group, set a group of related controls atomically). Relevant for display devices where scale_mode, anchor, position, and size are logically related, and for cameras where white balance, exposure, and gain belong together. The current flat list of (control_id, name, type, value) tuples does not capture this.

src/modules/discovery/discovery.c

@@ -76,19 +76,14 @@ static int find_slot(struct Discovery *d) {
 
 /* -- send ------------------------------------------------------------------ */
 
-static void send_announcement(struct Discovery *d) {
+static size_t build_announcement(struct Discovery *d, uint8_t *buf) {
-	size_t  name_len = strlen(d->config.name);
+	size_t name_len = strlen(d->config.name);
 	if (name_len > DISCOVERY_MAX_NAME_LEN) { name_len = DISCOVERY_MAX_NAME_LEN; }
 
 	uint32_t payload_len = (uint32_t)(ANN_FIXED_SIZE + name_len);
-	size_t   total       = TRANSPORT_FRAME_HEADER_SIZE + payload_len;
+	put_u16(buf, 0, 0x0010);
-	uint8_t  buf[TRANSPORT_FRAME_HEADER_SIZE + ANN_FIXED_SIZE + DISCOVERY_MAX_NAME_LEN];
-
-	/* frame header */
-	put_u16(buf, 0, 0x0010);       /* message_type: DISCOVERY_ANNOUNCE */
 	put_u32(buf, 2, payload_len);
 
-	/* announcement payload */
 	uint8_t *p = buf + TRANSPORT_FRAME_HEADER_SIZE;
 	put_u8 (p, ANN_PROTOCOL_VERSION, DISCOVERY_PROTOCOL_VERSION);
 	put_u16(p, ANN_SITE_ID,          d->config.site_id);
@@ -97,10 +92,26 @@ static void send_announcement(struct Discovery *d) {
 	put_u8 (p, ANN_NAME_LEN,         (uint8_t)name_len);
 	memcpy(p + ANN_NAME, d->config.name, name_len);
 
+	return TRANSPORT_FRAME_HEADER_SIZE + payload_len;
+}
+
+static void send_announcement(struct Discovery *d) {
+	uint8_t buf[TRANSPORT_FRAME_HEADER_SIZE + ANN_FIXED_SIZE + DISCOVERY_MAX_NAME_LEN];
+	size_t  total = build_announcement(d, buf);
 	sendto(d->sock, buf, total, 0,
 		(struct sockaddr *)&d->mcast_addr, sizeof(d->mcast_addr));
 }
 
+static void send_announcement_unicast(struct Discovery *d, uint32_t addr) {
+	uint8_t buf[TRANSPORT_FRAME_HEADER_SIZE + ANN_FIXED_SIZE + DISCOVERY_MAX_NAME_LEN];
+	size_t  total = build_announcement(d, buf);
+	struct sockaddr_in dest = {0};
+	dest.sin_family      = AF_INET;
+	dest.sin_port        = htons(DISCOVERY_PORT);
+	dest.sin_addr.s_addr = addr;
+	sendto(d->sock, buf, total, 0, (struct sockaddr *)&dest, sizeof(dest));
+}
+
 /* -- timeout check --------------------------------------------------------- */
 
 static void check_timeouts(struct Discovery *d) {
@@ -204,13 +215,16 @@ static void *receive_thread_fn(void *arg) {
 
 		uint32_t addr = src.sin_addr.s_addr;
 		uint64_t ts   = now_ms();
-		int      is_new = 0;
+		int      is_new        = 0;
+		int      reannounce    = 0;
 		struct Discovery_Peer peer_copy;
 
 		pthread_mutex_lock(&d->peers_mutex);
 
 		int idx = find_peer(d, addr, tcp_port);
 		if (idx >= 0) {
+			/* detect restart: same addr+port but site_id changed */
+			if (d->peers[idx].info.site_id != site_id) { reannounce = 1; }
 			d->peers[idx].last_seen_ms        = ts;
 			d->peers[idx].info.site_id        = site_id;
 			d->peers[idx].info.tcp_port       = tcp_port;
@@ -233,11 +247,12 @@ static void *receive_thread_fn(void *arg) {
 
 		pthread_mutex_unlock(&d->peers_mutex);
 
-		/* respond to every announcement — the sender may be a fresh instance
+		if (is_new || reannounce) {
-		 * that doesn't know about us yet even if we already have it in our table */
+			/* new peer, or peer restarted (site_id changed) — reply directly
-		pthread_mutex_lock(&d->announce_mutex);
+			 * to that host so it learns about us without waiting up to interval_ms.
-		pthread_cond_signal(&d->announce_cond);
+			 * Use unicast rather than multicast to avoid disturbing other nodes. */
-		pthread_mutex_unlock(&d->announce_mutex);
+			send_announcement_unicast(d, addr);
+		}
 
 		if (is_new && d->config.on_peer_found) {
 			d->config.on_peer_found(&peer_copy, d->config.userdata);

src/modules/protocol/protocol.c

@@ -420,7 +420,7 @@ struct App_Error proto_write_enum_devices_response(struct Transport_Conn *conn,
 		e = wbuf_i16(&b, d->win_y);     if (!APP_IS_OK(e)) { goto fail; }
 		e = wbuf_u16(&b, d->win_w);     if (!APP_IS_OK(e)) { goto fail; }
 		e = wbuf_u16(&b, d->win_h);     if (!APP_IS_OK(e)) { goto fail; }
-		e = wbuf_u8 (&b, d->scale);     if (!APP_IS_OK(e)) { goto fail; }
+		e = wbuf_u8 (&b, d->scale_mode); if (!APP_IS_OK(e)) { goto fail; }
 		e = wbuf_u8 (&b, d->anchor);    if (!APP_IS_OK(e)) { goto fail; }
 	}
 
@@ -624,11 +624,11 @@ struct App_Error proto_read_stop_ingest(
 }
 
 /* START_DISPLAY: request_id(2) cmd(2) stream_id(2) win_x(2) win_y(2)
- * win_w(2) win_h(2) scale(1) anchor(1) no_signal_fps(1) reserved(1) = 18 bytes */
+ * win_w(2) win_h(2) scale_mode(1) anchor(1) no_signal_fps(1) reserved(1) = 18 bytes */
 struct App_Error proto_write_start_display(struct Transport_Conn *conn,
 	uint16_t request_id, uint16_t stream_id,
 	int16_t win_x, int16_t win_y, uint16_t win_w, uint16_t win_h,
-	uint8_t scale, uint8_t anchor, uint8_t no_signal_fps)
+	uint8_t scale_mode, uint8_t anchor, uint8_t no_signal_fps)
 {
 	uint8_t buf[18];
 	uint32_t o = 0;
@@ -639,7 +639,7 @@ struct App_Error proto_write_start_display(struct Transport_Conn *conn,
 	put_i16(buf, o, win_y);                   o += 2;
 	put_u16(buf, o, win_w);                   o += 2;
 	put_u16(buf, o, win_h);                   o += 2;
-	put_u8 (buf, o, scale);                   o += 1;
+	put_u8 (buf, o, scale_mode);              o += 1;
 	put_u8 (buf, o, anchor);                  o += 1;
 	put_u8 (buf, o, no_signal_fps);           o += 1;
 	put_u8 (buf, o, 0);                       o += 1;  /* reserved */
@@ -669,7 +669,7 @@ struct App_Error proto_read_start_display(
 	out->win_y         = get_i16(payload,  8);
 	out->win_w         = get_u16(payload, 10);
 	out->win_h         = get_u16(payload, 12);
-	out->scale         = get_u8 (payload, 14);
+	out->scale_mode    = get_u8 (payload, 14);
 	out->anchor        = get_u8 (payload, 15);
 	out->no_signal_fps = length >= 18 ? get_u8(payload, 16) : 0;
 	return APP_OK;
@@ -731,7 +731,7 @@ struct App_Error proto_read_enum_devices_response(
 		uint16_t stream_id,
 		int16_t  win_x,  int16_t  win_y,
 		uint16_t win_w,  uint16_t win_h,
-		uint8_t  scale,  uint8_t  anchor,
+		uint8_t  scale_mode, uint8_t anchor,
 		void *userdata),
 	void *userdata)
 {
@@ -798,12 +798,12 @@ struct App_Error proto_read_enum_devices_response(
 			int16_t  win_y     = (int16_t)cur_u16(&c);
 			uint16_t win_w     = cur_u16(&c);
 			uint16_t win_h     = cur_u16(&c);
-			uint8_t  scale     = cur_u8(&c);
+			uint8_t  scale_mode = cur_u8(&c);
-			uint8_t  anchor    = cur_u8(&c);
+			uint8_t  anchor     = cur_u8(&c);
 			CUR_CHECK(c);
 			if (on_display) {
 				on_display(device_id, stream_id, win_x, win_y,
-					win_w, win_h, scale, anchor, userdata);
+					win_w, win_h, scale_mode, anchor, userdata);
 			}
 		}
 	}

src/node/main.c

@@ -178,7 +178,7 @@ struct Display_Slot {
 	/* Config — written by handle_start_display before setting wanted      */
 	int              win_x, win_y;
 	int              win_w, win_h;
-	Xorg_Scale       scale;
+	Xorg_Scale       scale_mode;
 	Xorg_Anchor      anchor;
 
 	/* Pending frame — deposited by transport thread, consumed by main     */
@@ -485,7 +485,7 @@ static void display_loop_tick(struct Node *node)
 				Xorg_Viewer *v = xorg_viewer_open(
 					d->win_x, d->win_y, d->win_w, d->win_h, title);
 				if (v) {
-					xorg_viewer_set_scale(v, d->scale);
+					xorg_viewer_set_scale(v, d->scale_mode);
 					xorg_viewer_set_anchor(v, d->anchor);
 					d->viewer = v;
 					pthread_mutex_lock(&d->mutex);
@@ -512,7 +512,7 @@ static void display_loop_tick(struct Node *node)
 
 		/* Sync scale/anchor — may be updated live via SET_CONTROL */
 		pthread_mutex_lock(&d->mutex);
-		Xorg_Scale  cur_scale  = d->scale;
+		Xorg_Scale  cur_scale  = d->scale_mode;
 		Xorg_Anchor cur_anchor = d->anchor;
 		pthread_mutex_unlock(&d->mutex);
 		xorg_viewer_set_scale(d->viewer, cur_scale);
@@ -889,7 +889,7 @@ static void handle_enum_devices(struct Node *node,
 			.win_y     = (int16_t)d->win_y,
 			.win_w     = (uint16_t)d->win_w,
 			.win_h     = (uint16_t)d->win_h,
-			.scale     = (uint8_t)d->scale,
+			.scale_mode = (uint8_t)d->scale_mode,
 			.anchor    = (uint8_t)d->anchor,
 		};
 		pthread_mutex_unlock(&d->mutex);
@@ -923,15 +923,15 @@ static void handle_enum_controls(struct Node *node,
 			return;
 		}
 		pthread_mutex_lock(&disp->mutex);
-		int scale         = (int)disp->scale;
+		int scale_mode    = (int)disp->scale_mode;
 		int anchor        = (int)disp->anchor;
 		int no_signal_fps = disp->no_signal_fps > 0 ? disp->no_signal_fps : 15;
 		pthread_mutex_unlock(&disp->mutex);
 		struct Proto_Control_Info ctrls[] = {
-			{ .id = PROTO_DISPLAY_CTRL_SCALE,
+			{ .id = PROTO_DISPLAY_CTRL_SCALE_MODE,
-			  .type = 1, .name = "Scale",
+			  .type = 1, .name = "Scale Mode",
 			  .min = 0, .max = 3, .step = 1, .default_val = 1,
-			  .current_val = scale },
+			  .current_val = scale_mode },
 			{ .id = PROTO_DISPLAY_CTRL_ANCHOR,
 			  .type = 1, .name = "Anchor",
 			  .min = 0, .max = 1, .step = 1, .default_val = 0,
@@ -981,7 +981,7 @@ static void handle_get_control(struct Node *node,
 		int32_t value = 0;
 		int found = 1;
 		switch (req.control_id) {
-		case PROTO_DISPLAY_CTRL_SCALE:         value = (int32_t)disp->scale; break;
+		case PROTO_DISPLAY_CTRL_SCALE_MODE:         value = (int32_t)disp->scale_mode; break;
 		case PROTO_DISPLAY_CTRL_ANCHOR:        value = (int32_t)disp->anchor; break;
 		case PROTO_DISPLAY_CTRL_NO_SIGNAL_FPS: value = disp->no_signal_fps > 0 ? disp->no_signal_fps : 15; break;
 		default: found = 0; break;
@@ -1032,9 +1032,9 @@ static void handle_set_control(struct Node *node,
 		pthread_mutex_lock(&disp->mutex);
 		int found = 1;
 		switch (req.control_id) {
-		case PROTO_DISPLAY_CTRL_SCALE:
+		case PROTO_DISPLAY_CTRL_SCALE_MODE:
 			if (req.value >= 0 && req.value <= 3) {
-				disp->scale = (Xorg_Scale)req.value;
+				disp->scale_mode = (Xorg_Scale)req.value;
 			}
 			break;
 		case PROTO_DISPLAY_CTRL_ANCHOR:
@@ -1250,7 +1250,7 @@ static void handle_start_display(struct Node *node,
 	d->win_y        = (int)req.win_y;
 	d->win_w        = req.win_w > 0 ? (int)req.win_w : 1280;
 	d->win_h        = req.win_h > 0 ? (int)req.win_h : 720;
-	d->scale          = proto_scale_to_xorg(req.scale);
+	d->scale_mode     = proto_scale_to_xorg(req.scale_mode);
 	d->anchor         = proto_anchor_to_xorg(req.anchor);
 	d->no_signal_fps  = req.no_signal_fps > 0 ? (int)req.no_signal_fps : 15;
 	d->wanted_state   = DISP_OPEN;  /* reconciled by display_loop_tick */