3 files changed, 38 insertions, 0 deletions
diff --git a/backend/drm/atomic.c b/backend/drm/atomic.c
index 82ead96e..ab1b2160 100644
--- a/backend/drm/atomic.c
+++ b/backend/drm/atomic.c
@@ -284,6 +284,9 @@ static bool atomic_crtc_commit(struct wlr_drm_connector *conn,
 		atomic_add(&atom, conn->id, conn->props.content_type,
 			DRM_MODE_CONTENT_TYPE_GRAPHICS);
 	}
+	if (active && conn->props.max_bpc != 0 && conn->max_bpc > 0) {
+		atomic_add(&atom, conn->id, conn->props.max_bpc, conn->max_bpc);
+	}
 	atomic_add(&atom, crtc->id, crtc->props.mode_id, mode_id);
 	atomic_add(&atom, crtc->id, crtc->props.active, active);
 	if (active) {
diff --git a/backend/drm/drm.c b/backend/drm/drm.c
index 1c22878c..262a533e 100644
--- a/backend/drm/drm.c
+++ b/backend/drm/drm.c
@@ -1317,6 +1317,14 @@ void scan_drm_connectors(struct wlr_drm_backend *drm,
 				wlr_conn->output.non_desktop = non_desktop;
 			}
 
+			wlr_conn->max_bpc = 0;
+			if (wlr_conn->props.max_bpc != 0) {
+				if (!introspect_drm_prop_range(drm->fd, wlr_conn->props.max_bpc,
+						NULL, &wlr_conn->max_bpc)) {
+					wlr_log(WLR_ERROR, "Failed to introspect 'max bpc' property");
+				}
+			}
+
 			size_t edid_len = 0;
 			uint8_t *edid = get_drm_prop_blob(drm->fd,
 				wlr_conn->id, wlr_conn->props.edid, &edid_len);
diff --git a/backend/drm/properties.c b/backend/drm/properties.c
index 51fbc80a..4f495177 100644
--- a/backend/drm/properties.c
+++ b/backend/drm/properties.c
@@ -1,4 +1,5 @@
 #define _POSIX_C_SOURCE 200809L
+#include <assert.h>
 #include <stdbool.h>
 #include <stddef.h>
 #include <stdint.h>
@@ -26,6 +27,7 @@ static const struct prop_info connector_info[] = {
 	{ "PATH", INDEX(path) },
 	{ "content type", INDEX(content_type) },
 	{ "link-status", INDEX(link_status) },
+	{ "max bpc", INDEX(max_bpc) },
 	{ "non-desktop", INDEX(non_desktop) },
 	{ "panel orientation", INDEX(panel_orientation) },
 	{ "subconnector", INDEX(subconnector) },
@@ -181,3 +183,28 @@ char *get_drm_prop_enum(int fd, uint32_t obj, uint32_t prop_id) {
 
 	return str;
 }
+
+bool introspect_drm_prop_range(int fd, uint32_t prop_id,
+		uint64_t *min, uint64_t *max) {
+	drmModePropertyRes *prop = drmModeGetProperty(fd, prop_id);
+	if (!prop) {
+		return false;
+	}
+
+	if (drmModeGetPropertyType(prop) != DRM_MODE_PROP_RANGE) {
+		drmModeFreeProperty(prop);
+		return false;
+	}
+
+	assert(prop->count_values == 2);
+
+	if (min != NULL) {
+		*min = prop->values[0];
+	}
+	if (max != NULL) {
+		*max = prop->values[1];
+	}
+
+	drmModeFreeProperty(prop);
+	return true;
+}