Re: [PATCH v8 1/3] gpu: drm: separate panel orientation property creating and value setting

Hsin-Yi Wang hsinyi@chromium.org writes:

drm_dev_register() sets connector->registration_state to DRM_CONNECTOR_REGISTERED and dev->registered to true. If drm_connector_set_panel_orientation() is first called after drm_dev_register(), it will fail several checks and results in following warning.

Hi,

I stumbled upon this when investigating the same WARN_ON on amdgpu. Thanks for the patch :)

diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c index a50c82bc2b2fec..572ead7ac10690 100644 --- a/drivers/gpu/drm/drm_connector.c +++ b/drivers/gpu/drm/drm_connector.c @@ -1252,7 +1252,7 @@ static const struct drm_prop_enum_list dp_colorspaces[] = {

• INPUT_PROP_DIRECT) will still map 1:1 to the actual LCD panel
• coordinates, so if userspace rotates the picture to adjust for
• the orientation it must also apply the same transformation to the

• • touchscreen input coordinates. This property is initialized by calling

• • touchscreen input coordinates. This property value is set by calling
  • drm_connector_set_panel_orientation() or
  • drm_connector_set_panel_orientation_with_quirk()

@@ -2341,8 +2341,8 @@ EXPORT_SYMBOL(drm_connector_set_vrr_capable_property);

• @connector: connector for which to set the panel-orientation property.
• @panel_orientation: drm_panel_orientation value to set

• • This function sets the connector's panel_orientation and attaches
• • a "panel orientation" property to the connector.

• • This function sets the connector's panel_orientation value. If the property
• • doesn't exist, it will try to create one.
  • Calling this function on a connector where the panel_orientation has
  • already been set is a no-op (e.g. the orientation has been overridden with

@@ -2373,19 +2373,12 @@ int drm_connector_set_panel_orientation( info->panel_orientation = panel_orientation;

prop = dev->mode_config.panel_orientation_property;

• if (!prop) {

• prop = drm_property_create_enum(dev, DRM_MODE_PROP_IMMUTABLE,
  

• 		"panel orientation",
  

• 		drm_panel_orientation_enum_list,
  

• 		ARRAY_SIZE(drm_panel_orientation_enum_list));
  

• if (!prop)
  

• 	return -ENOMEM;
  

• dev->mode_config.panel_orientation_property = prop;
  

• }

• if (!prop &&

•    drm_connector_init_panel_orientation_property(connector) < 0)
  

• return -ENOMEM;
  
  

In the case where the property has not been created beforehand, you forgot to reinitialize prop here, after calling drm_connector_init_panel_orientation_property(). This means drm_object_property_set_value() will be called with a NULL second argument and Oops the kernel.

• drm_object_attach_property(&connector->base, prop,

• 		   info->panel_orientation);
  

• drm_object_property_set_value(&connector->base, prop,

• 		      info->panel_orientation);