drm/panel: simple: Set appropriate mode type

All modes exposed by simple panels should be tagged as driver defined
modes. Moreover, if a panel supports only one mode, this mode is
obviously the preferred one.

Doing this also fix a problem occurring when a 'video=' parameter is
passed on the kernel command line. In some cases the user provided mode
will be preferred over the simple panel ones, which might result in
unpredictable behavior.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Reviewed-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Tested-by: Nicolas Ferre <nicolas.ferre@atmel.com>
[treding@nvidia.com: reshuffle some code for consistency]
Signed-off-by: Thierry Reding <treding@nvidia.com>

drivers/gpu/drm/panel/panel-simple.c

@@ -117,6 +117,12 @@ static int panel_simple_get_fixed_modes(struct panel_simple *panel)
 		}
 
 		drm_display_mode_from_videomode(&vm, mode);
+
+		mode->type |= DRM_MODE_TYPE_DRIVER;
+
+		if (panel->desc->num_modes == 1)
+			mode->type |= DRM_MODE_TYPE_PREFERRED;
+
 		drm_mode_set_name(mode);
 
 		drm_mode_probed_add(connector, mode);
@@ -133,6 +139,11 @@ static int panel_simple_get_fixed_modes(struct panel_simple *panel)
 			continue;
 		}
 
+		mode->type |= DRM_MODE_TYPE_DRIVER;
+
+		if (panel->desc->num_modes == 1)
+			mode->type |= DRM_MODE_TYPE_PREFERRED;
+
 		drm_mode_set_name(mode);
 
 		drm_mode_probed_add(connector, mode);