Re: [PATCH] nouveau: use proper atomic accessor to get crtc state

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Mon, Dec 01, 2025 at 07:42:06AM +1000, Dave Airlie wrote:
> From: Dave Airlie <airlied@redhat.com>
> 
> This gets the crtc state from the current state, instead of
> trying to lookup or create a state.
> 
> atomic core started warning about this recently.
> 
> Fixes: 0a0e79a2d9ed ("drm/atomic: WARN about invalid drm_foo_get_state() usage")
> Signed-off-by: Dave Airlie <airlied@redhat.com>
> ---
>  drivers/gpu/drm/nouveau/dispnv50/atom.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/nouveau/dispnv50/atom.h b/drivers/gpu/drm/nouveau/dispnv50/atom.h
> index 93f8f4f64578..ada8fb6f1a9a 100644
> --- a/drivers/gpu/drm/nouveau/dispnv50/atom.h
> +++ b/drivers/gpu/drm/nouveau/dispnv50/atom.h
> @@ -151,7 +151,7 @@ struct nv50_head_atom {
>  static inline struct nv50_head_atom *
>  nv50_head_atom_get(struct drm_atomic_state *state, struct drm_crtc *crtc)
>  {
> -	struct drm_crtc_state *statec = drm_atomic_get_crtc_state(state, crtc);
> +	struct drm_crtc_state *statec = drm_atomic_get_new_crtc_state(state, crtc);
>  	if (IS_ERR(statec))

drm_atomic_get_new_crtc_state() will never return an error.
It's either a valid pointer or NULL.

The somewhat oddball terminology used in the nouveau code makes it
a bit hard to read, but to me it looks like this this is only used
to get the crtc state for a plane's old/new crtc. Those should always
be included in the atomic state along with the plane itself, so I
*think* you could just nuke all the error checks in the callers and
not bother with any NULL checks.

>  		return (void *)statec;
>  	return nv50_head_atom(statec);
> -- 
> 2.51.1

-- 
Ville Syrjälä
Intel