backend-drm: Parse KMS panel orientation property, apply to weston_head

The KMS 'panel orientation' property allows the driver to statically
declare a fixed rotation of an output device. Now that weston_head has a
transform member, plumb the KMS property through to weston_head so the
compositor can make a smarter choice out of the box.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
[daniels: Extracted from one of Lucas's patches]
Signed-off-by: Daniel Stone <daniels@collabora.com>

libweston/backend-drm/drm-internal.h

@@ -200,6 +200,7 @@ enum wdrm_connector_property {
 	WDRM_CONNECTOR_NON_DESKTOP,
 	WDRM_CONNECTOR_CONTENT_PROTECTION,
 	WDRM_CONNECTOR_HDCP_CONTENT_TYPE,
+	WDRM_CONNECTOR_PANEL_ORIENTATION,
 	WDRM_CONNECTOR__COUNT
 };
 
@@ -224,6 +225,14 @@ enum wdrm_dpms_state {
 	WDRM_DPMS_STATE__COUNT
 };
 
+enum wdrm_panel_orientation {
+	WDRM_PANEL_ORIENTATION_NORMAL = 0,
+	WDRM_PANEL_ORIENTATION_UPSIDE_DOWN,
+	WDRM_PANEL_ORIENTATION_LEFT_SIDE_UP,
+	WDRM_PANEL_ORIENTATION_RIGHT_SIDE_UP,
+	WDRM_PANEL_ORIENTATION__COUNT
+};
+
 /**
  * List of properties attached to DRM CRTCs
  */

libweston/backend-drm/kms.c

@@ -116,6 +116,13 @@ struct drm_property_enum_info hdcp_content_type_enums[] = {
 	},
 };
 
+struct drm_property_enum_info panel_orientation_enums[] = {
+	[WDRM_PANEL_ORIENTATION_NORMAL] = { .name = "Normal", },
+	[WDRM_PANEL_ORIENTATION_UPSIDE_DOWN] = { .name = "Upside Down", },
+	[WDRM_PANEL_ORIENTATION_LEFT_SIDE_UP] = { .name = "Left Side Up", },
+	[WDRM_PANEL_ORIENTATION_RIGHT_SIDE_UP] = { .name = "Right Side Up", },
+};
+
 const struct drm_property_info connector_props[] = {
 	[WDRM_CONNECTOR_EDID] = { .name = "EDID" },
 	[WDRM_CONNECTOR_DPMS] = {
@@ -135,6 +142,11 @@ const struct drm_property_info connector_props[] = {
 		.enum_values = hdcp_content_type_enums,
 		.num_enum_values = WDRM_HDCP_CONTENT_TYPE__COUNT,
 	},
+	[WDRM_CONNECTOR_PANEL_ORIENTATION] = {
+		.name = "panel orientation",
+		.enum_values = panel_orientation_enums,
+		.num_enum_values = WDRM_PANEL_ORIENTATION__COUNT,
+	},
 };
 
 const struct drm_property_info crtc_props[] = {

libweston/backend-drm/modes.c

@@ -128,6 +128,29 @@ check_non_desktop(struct drm_head *head, drmModeObjectPropertiesPtr props)
 	return drm_property_get_value(non_desktop_info, props, 0);
 }
 
+static uint32_t
+get_panel_orientation(struct drm_head *head, drmModeObjectPropertiesPtr props)
+{
+	struct drm_property_info *orientation =
+		&head->props_conn[WDRM_CONNECTOR_PANEL_ORIENTATION];
+	uint64_t kms_val =
+		drm_property_get_value(orientation, props,
+				       WDRM_PANEL_ORIENTATION_NORMAL);
+
+	switch (kms_val) {
+	case WDRM_PANEL_ORIENTATION_NORMAL:
+		return WL_OUTPUT_TRANSFORM_NORMAL;
+	case WDRM_PANEL_ORIENTATION_UPSIDE_DOWN:
+		return WL_OUTPUT_TRANSFORM_180;
+	case WDRM_PANEL_ORIENTATION_LEFT_SIDE_UP:
+		return WL_OUTPUT_TRANSFORM_90;
+	case WDRM_PANEL_ORIENTATION_RIGHT_SIDE_UP:
+		return WL_OUTPUT_TRANSFORM_270;
+	default:
+		assert(!"unknown property value in get_panel_orientation");
+	}
+}
+
 static int
 parse_modeline(const char *s, drmModeModeInfo *mode)
 {
@@ -500,6 +523,9 @@ update_head_from_connector(struct drm_head *head,
 	weston_head_set_physical_size(&head->base, head->connector->mmWidth,
 				      head->connector->mmHeight);
 
+	weston_head_set_transform(&head->base,
+				  get_panel_orientation(head, props));
+
 	/* Unknown connection status is assumed disconnected. */
 	weston_head_set_connection_status(&head->base,
 			head->connector->connection == DRM_MODE_CONNECTED);