backend/drm: parse TILE property

backend/drm/drm.c

@@ -15,6 +15,7 @@
 #include <wlr/interfaces/wlr_output.h>
 #include <wlr/render/drm_syncobj.h>
 #include <wlr/render/wlr_renderer.h>
+#include <wlr/types/wlr_output_group.h>
 #include <wlr/util/box.h>
 #include <wlr/util/log.h>
 #include <wlr/util/transform.h>
@@ -1720,6 +1721,12 @@ static bool connect_drm_connector(struct wlr_drm_connector *wlr_conn,
 	parse_edid(wlr_conn, edid_len, edid);
 	free(edid);
 
+	size_t tile_len = 0;
+	uint8_t *tile = get_drm_prop_blob(drm->fd,
+		wlr_conn->id, wlr_conn->props.tile, &tile_len);
+	parse_tile(wlr_conn, tile_len, tile);
+	free(tile);
+
 	char *subconnector = NULL;
 	if (wlr_conn->props.subconnector) {
 		subconnector = get_drm_prop_enum(drm->fd,

backend/drm/properties.c

@@ -27,6 +27,7 @@ static const struct prop_info connector_info[] = {
 	{ "EDID", INDEX(edid) },
 	{ "HDR_OUTPUT_METADATA", INDEX(hdr_output_metadata) },
 	{ "PATH", INDEX(path) },
+	{ "TILE", INDEX(tile) },
 	{ "content type", INDEX(content_type) },
 	{ "link-status", INDEX(link_status) },
 	{ "max bpc", INDEX(max_bpc) },

backend/drm/util.c

@@ -97,6 +97,47 @@ void parse_edid(struct wlr_drm_connector *conn, size_t len, const uint8_t *data)
 	di_info_destroy(info);
 }
 
+void parse_tile(struct wlr_drm_connector *conn, size_t len, const uint8_t *data) {
+	struct wlr_output_group_tile_info *tile_info = &conn->tile_info;
+	memset(tile_info, 0, sizeof(*tile_info));
+	if (len == 0)
+		return;
+
+	// Reference:
+	// - include/linux/drm/drm_connector.h tile_blob_ptr
+	// - drivers/gpu/drm/drm_edid.c drm_parse_tiled_block()
+	//
+	// Note: group_id is always > 0
+	int ret = sscanf((char*)data, "%d:%d:%d:%d:%d:%d:%d:%d",
+		&tile_info->group_id,
+		&tile_info->is_single_monitor,
+		&tile_info->num_h,
+		&tile_info->num_v,
+		&tile_info->h_loc,
+		&tile_info->v_loc,
+		&tile_info->h_size,
+		&tile_info->v_size);
+	if(ret != 8) {
+		wlr_log(WLR_ERROR, "Unable to understand tile information for "
+			"connector %s", conn->name);
+		return;
+	}
+
+	wlr_log(WLR_INFO, "Connector '%s' TILE information: "
+		"group ID %d, single monitor %d, total %d horizontal tiles, "
+		"total %d vertical tiles, horizontal tile %d, vertical tile "
+		"%d, width %d, height %d",
+		conn->name,
+		tile_info->group_id,
+		tile_info->is_single_monitor,
+		tile_info->num_h,
+		tile_info->num_v,
+		tile_info->h_loc,
+		tile_info->v_loc,
+		tile_info->h_size,
+		tile_info->v_size);
+}
+
 const char *drm_connector_status_str(drmModeConnection status) {
 	switch (status) {
 	case DRM_MODE_CONNECTED:

include/backend/drm/drm.h

@@ -10,6 +10,7 @@
 #include <wlr/backend/session.h>
 #include <wlr/render/drm_format_set.h>
 #include <wlr/types/wlr_output_layer.h>
+#include <wlr/types/wlr_output_group.h>
 #include <xf86drmMode.h>
 #include "backend/drm/iface.h"
 #include "backend/drm/properties.h"
@@ -219,6 +220,8 @@ struct wlr_drm_connector {
 	uint32_t hdr_output_metadata;
 
 	int32_t refresh;
+
+	struct wlr_output_group_tile_info tile_info;
 };
 
 struct wlr_drm_backend *get_drm_backend_from_backend(

include/backend/drm/properties.h

@@ -22,6 +22,7 @@ struct wlr_drm_connector_props {
 	uint32_t panel_orientation; // not guaranteed to exist
 	uint32_t content_type; // not guaranteed to exist
 	uint32_t max_bpc; // not guaranteed to exist
+	uint32_t tile; // not guaranteed to exist
 
 	// atomic-modesetting only
 

include/backend/drm/util.h

@@ -14,6 +14,7 @@ enum wlr_output_mode_aspect_ratio get_picture_aspect_ratio(const drmModeModeInfo
 const char *get_pnp_manufacturer(const char code[static 3]);
 // Populates the make/model/phys_{width,height} of output from the edid data
 void parse_edid(struct wlr_drm_connector *conn, size_t len, const uint8_t *data);
+void parse_tile(struct wlr_drm_connector *conn, size_t len, const uint8_t *data);
 const char *drm_connector_status_str(drmModeConnection status);
 void generate_cvt_mode(drmModeModeInfo *mode, int hdisplay, int vdisplay,
 	float vrefresh);