On Fri, Dec 31, 2021 at 03:23:31PM +0200, Jani Nikula wrote:
> On Wed, 12 Jul 2017, ville.syrjala@xxxxxxxxxxxxxxx wrote:
> > From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> >
> > Make the atomic private object stuff less special by introducing proper
> > base classes for the object and its state. Drivers can embed these in
> > their own appropriate objects, after which these things will work
> > exactly like the plane/crtc/connector states during atomic operations.
> >
> > v2: Reorder to not depend on drm_dynarray (Daniel)
> >
> > Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan@xxxxxxxxx>
> > Cc: Daniel Vetter <daniel.vetter@xxxxxxxx>
> > Reviewed-by: Daniel Vetter <daniel.vetter@xxxxxxxx> #v1
> > Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
>
> Stumbled upon an old commit
>
> commit a4370c777406c2810e37fafd166ccddecdb2a60c
> Author: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> Date: Wed Jul 12 18:51:02 2017 +0300
>
> drm/atomic: Make private objs proper objects
>
> which is this patch.
>
> > @@ -3050,8 +3043,7 @@ struct drm_dp_mst_topology_state *drm_atomic_get_mst_topology_state(struct drm_a
> > struct drm_device *dev = mgr->dev;
> >
> > WARN_ON(!drm_modeset_is_locked(&dev->mode_config.connection_mutex));
> > - return drm_atomic_get_private_obj_state(state, mgr,
> > - &mst_state_funcs);
> > + return to_dp_mst_topology_state(drm_atomic_get_private_obj_state(state, &mgr->base));
> > }
> > EXPORT_SYMBOL(drm_atomic_get_mst_topology_state);
>
> I don't think this combines well with...
>
> > diff --git a/include/drm/drm_dp_mst_helper.h b/include/drm/drm_dp_mst_helper.h
> > index 177ab6f86855..d55abb75f29a 100644
> > --- a/include/drm/drm_dp_mst_helper.h
> > +++ b/include/drm/drm_dp_mst_helper.h
> > @@ -404,12 +404,17 @@ struct drm_dp_payload {
> > int vcpi;
> > };
> >
> > +#define to_dp_mst_topology_state(x) container_of(x, struct drm_dp_mst_topology_state, base)
>
> ...this in case of error pointers that
> drm_atomic_get_private_obj_state() may return.
offsetof(base)==0 so should work in practice.
--
Ville Syrjälä
Intel
