Log current planes on apply

It is helpful for debugging to know in which state the available planes on an
output are when a layout is applied that leads to a change.

For that log all planes that are compatible with the output. Currently disabled
planes have multiple properties logged per line to keep the log short.

alloc.c

@@ -602,6 +602,7 @@ bool liftoff_output_apply(struct liftoff_output *output, drmModeAtomicReq *req)
 	}
 	log_no_reuse(output);
 
+	output_log_planes(output);
 	output_log_layers(output);
 
 	/* Unset all existing plane and layer mappings. */

include/private.h

@@ -98,6 +98,7 @@ struct liftoff_plane_property *plane_get_property(struct liftoff_plane *plane,
 bool plane_apply(struct liftoff_plane *plane, struct liftoff_layer *layer,
 		 drmModeAtomicReq *req, bool *compatible);
 
+void output_log_planes(struct liftoff_output *output);
 void output_log_layers(struct liftoff_output *output);
 
 #endif

output.c

@@ -55,6 +55,99 @@ void liftoff_output_set_composition_layer(struct liftoff_output *output,
 	output->composition_layer = layer;
 }
 
+void output_log_planes(struct liftoff_output *output)
+{
+	struct liftoff_device *device;
+	struct liftoff_plane *plane;
+	drmModeObjectProperties *drm_props;
+	drmModePropertyRes *drm_prop;
+	size_t i;
+	int per_line, max_per_line;
+
+	device = output->device;
+
+	if (!log_has(LIFTOFF_DEBUG)) {
+		return;
+	}
+
+	liftoff_log(LIFTOFF_DEBUG, "Planes on CRTC %"PRIu32":", output->crtc_id);
+
+	liftoff_list_for_each(plane, &device->planes, link) {
+		bool active = false;
+
+		if ((plane->possible_crtcs & (1 << output->crtc_index)) == 0) {
+			continue;
+		}
+
+
+		drm_props = drmModeObjectGetProperties(device->drm_fd,
+			plane->id, DRM_MODE_OBJECT_PLANE);
+		if (drm_props == NULL) {
+			liftoff_log_errno(LIFTOFF_ERROR, "drmModeObjectGetProperties");
+			continue;
+		}
+
+		for (i = 0; i < drm_props->count_props; i++) {
+			drm_prop = drmModeGetProperty(device->drm_fd, drm_props->props[i]);
+			if (drm_prop == NULL) {
+				liftoff_log_errno(LIFTOFF_ERROR, "drmModeObjectGetProperties");
+				continue;
+			}
+
+			if (strcmp(drm_prop->name, "CRTC_ID") == 0
+					&& drm_props->prop_values[i] != 0) {
+				active = true;
+				break;
+			}
+		}
+
+		struct liftoff_log_buffer log_buf = {0};
+		liftoff_log_buffer_append(&log_buf, "  Plane %"PRIu32 "%s", plane->id,
+			active ? ":" : " (inactive):");
+
+		max_per_line = active ? 1 : 4;
+		per_line = max_per_line - 1;
+		for (i = 0; i < drm_props->count_props; i++) {
+			uint64_t value = drm_props->prop_values[i];
+			char *name;
+
+			if (++per_line == max_per_line) {
+				liftoff_log_buffer_append(&log_buf, "\n   ");
+				per_line = 0;
+			}
+
+			drm_prop = drmModeGetProperty(device->drm_fd,
+				drm_props->props[i]);
+			if (drm_prop == NULL) {
+				liftoff_log_buffer_append(&log_buf, "ERR!");
+				continue;
+			}
+
+			name = drm_prop->name;
+
+			if (strcmp(name, "type") == 0) {
+				liftoff_log_buffer_append(&log_buf, " %s: %s", name,
+				value == DRM_PLANE_TYPE_PRIMARY ? "primary" :
+				value == DRM_PLANE_TYPE_CURSOR ? "cursor" : "overlay");
+				continue;
+			}
+
+			if (strcmp(name, "CRTC_X") == 0 || strcmp(name, "CRTC_Y") == 0
+					|| strcmp(name, "IN_FENCE_FD") == 0) {
+				liftoff_log_buffer_append(&log_buf, " %s: %"PRIi32, name,
+					(int32_t)value);
+				continue;
+			}
+
+			if (strcmp(name, "SRC_W") == 0 || strcmp(name, "SRC_H") == 0) {
+				value = value >> 16;
+			}
+			liftoff_log_buffer_append(&log_buf, " %s: %"PRIu64, name, value);
+		}
+		liftoff_log_buffer_flush(&log_buf, LIFTOFF_DEBUG);
+	}
+}
+
 void output_log_layers(struct liftoff_output *output) {
 	struct liftoff_layer *layer;
 	size_t i;
@@ -63,7 +156,7 @@ void output_log_layers(struct liftoff_output *output) {
 		return;
 	}
 
-	liftoff_log(LIFTOFF_DEBUG, "Layers on CRTC %"PRIu32":", output->crtc_id);
+	liftoff_log(LIFTOFF_DEBUG, "Available layers:");
 	liftoff_list_for_each(layer, &output->layers, link) {
 		if (layer->force_composition) {
 			liftoff_log(LIFTOFF_DEBUG, "  Layer %p "