On Tue, Feb 15, 2022 at 9:17 AM Gabriel Krisman Bertazi
<krisman@xxxxxxxxxxxxx> wrote:
>
> Hsin-Yi Wang <hsinyi@xxxxxxxxxxxx> 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
hi Gabriel,
drm_connector_init_panel_orientation_property() will create prop if
it's null. If prop fails to be created there, it will return -ENOMEM.
> 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);
>
>
> --
> Gabriel Krisman Bertazi
