Re: [PATCH v2 06/11] drm: Use state helper instead of plane state pointer in atomic_check

[Maxime Ripard]

Hi Ville,

On Fri, Jan 22, 2021 at 02:07:22PM +0200, Ville Syrjälä wrote:
> On Thu, Jan 21, 2021 at 05:35:31PM +0100, Maxime Ripard wrote:
> > Many drivers reference the plane->state pointer in order to get the
> > current plane state in their atomic_check hook, which would be the old
> > plane state in the global atomic state since _swap_state hasn't happened
> > when atomic_check is run.
> > 
> > Use the drm_atomic_get_old_plane_state helper to get that state to make
> > it more obvious.
> > 
> > This was made using the coccinelle script below:
> > 
> > @ plane_atomic_func @
> > identifier helpers;
> > identifier func;
> > @@
> > 
> > static struct drm_plane_helper_funcs helpers = {
> > 	...,
> > 	.atomic_check = func,
> > 	...,
> > };
> > 
> > @ replaces_old_state @
> > identifier plane_atomic_func.func;
> > identifier plane, state, plane_state;
> > @@
> > 
> >  func(struct drm_plane *plane, struct drm_atomic_state *state) {
> >  	...
> > -	struct drm_plane_state *plane_state = plane->state;
> > +	struct drm_plane_state *plane_state = drm_atomic_get_old_plane_state(state, plane);
> >  	...
> >  }
> > 
> > @@
> > identifier plane_atomic_func.func;
> > identifier plane, state, plane_state;
> > @@
> > 
> >  func(struct drm_plane *plane, struct drm_atomic_state *state) {
> >  	struct drm_plane_state *plane_state = drm_atomic_get_old_plane_state(state, plane);
> >  	...
> > -	plane->state
> > +	plane_state
> >  	...
> 
> We don't need the <... ...> style here? It's been a while since
> I did any serious cocci so I'm getting a bit rusty on the details...

You're right, I've changed it and caught some more users (ingenic). I'll update it.

> Otherwise looks great
> Reviewed-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>

Thanks!
Maxime

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