backend/drm: pass through mode picture aspect ratio

backend/drm/drm.c

@@ -760,6 +760,7 @@ static struct wlr_drm_mode *drm_mode_create(const drmModeModeInfo *modeinfo) {
 	mode->wlr_mode.width = mode->drm_mode.hdisplay;
 	mode->wlr_mode.height = mode->drm_mode.vdisplay;
 	mode->wlr_mode.refresh = calculate_refresh_rate(modeinfo);
+	mode->wlr_mode.picture_aspect_ratio = get_picture_aspect_ratio(modeinfo);
 	if (modeinfo->type & DRM_MODE_TYPE_PREFERRED) {
 		mode->wlr_mode.preferred = true;
 	}

backend/drm/util.c

@@ -30,6 +30,25 @@ int32_t calculate_refresh_rate(const drmModeModeInfo *mode) {
 	return refresh;
 }
 
+enum wlr_output_mode_aspect_ratio get_picture_aspect_ratio(const drmModeModeInfo *mode) {
+	switch (mode->flags & DRM_MODE_FLAG_PIC_AR_MASK) {
+	case DRM_MODE_FLAG_PIC_AR_NONE:
+		return WLR_OUTPUT_MODE_ASPECT_RATIO_NONE;
+	case DRM_MODE_FLAG_PIC_AR_4_3:
+		return WLR_OUTPUT_MODE_ASPECT_RATIO_4_3;
+	case DRM_MODE_FLAG_PIC_AR_16_9:
+		return WLR_OUTPUT_MODE_ASPECT_RATIO_16_9;
+	case DRM_MODE_FLAG_PIC_AR_64_27:
+		return WLR_OUTPUT_MODE_ASPECT_RATIO_64_27;
+	case DRM_MODE_FLAG_PIC_AR_256_135:
+		return WLR_OUTPUT_MODE_ASPECT_RATIO_256_135;
+	default:
+		wlr_log(WLR_ERROR, "Unknown mode picture aspect ratio: %u",
+			mode->flags & DRM_MODE_FLAG_PIC_AR_MASK);
+		return WLR_OUTPUT_MODE_ASPECT_RATIO_NONE;
+	}
+}
+
 static const char *get_manufacturer(struct udev_hwdb *hwdb, uint16_t code) {
 	static char pnp_id[4];
 

include/backend/drm/util.h

@@ -9,6 +9,7 @@ struct wlr_drm_connector;
 
 // Calculates a more accurate refresh rate (mHz) than what mode itself provides
 int32_t calculate_refresh_rate(const drmModeModeInfo *mode);
+enum wlr_output_mode_aspect_ratio get_picture_aspect_ratio(const drmModeModeInfo *mode);
 // 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);