Re: [PATCH v3 3/4] drm/i915: Avoid programming color HW blocks for NV12 Y planes

[Jani Nikula <jani.nikula@linux.intel.com>]

On Mon, 11 May 2026, Chaitanya Kumar Borah <chaitanya.kumar.borah@intel.com> wrote:
> link_nv12_planes() currently copies the full UV plane hw state to
> the Y plane. This includes the color pipeline blobs (ctm, degamma_lut,
> gamma_lut, lut_3d) which is incorrect as we don't need to program these
> HW blocks for Y plane.
>
> This is harmless currently as the color pipeline uapi does not support
> YUV (both packed and planar) formats but that can change in the future.
>
> Add a new static helper intel_plane_y_copy_hw_state() that copies only
> the rendering parameters a Y plane actually needs, leaving all color
> pipeline blobs unset. Remove the helper intel_plane_copy_hw_state() as
> there are no users for it.
>
> Assisted-by: GitHub Copilot:Claude Sonnet 4.6
> Signed-off-by: Chaitanya Kumar Borah <chaitanya.kumar.borah@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_plane.c | 26 +++++++++++++---------
>  drivers/gpu/drm/i915/display/intel_plane.h |  2 --
>  2 files changed, 16 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_plane.c b/drivers/gpu/drm/i915/display/intel_plane.c
> index a8efe0011b23..559eef467dda 100644
> --- a/drivers/gpu/drm/i915/display/intel_plane.c
> +++ b/drivers/gpu/drm/i915/display/intel_plane.c
> @@ -450,16 +450,22 @@ void intel_plane_copy_uapi_to_hw_state(struct intel_atomic_state *state,
>  	intel_plane_color_copy_uapi_to_hw_state(state, plane_state, from_plane_state, crtc);
>  }
>  
> -void intel_plane_copy_hw_state(struct intel_plane_state *plane_state,
> -			       const struct intel_plane_state *from_plane_state)
> +static void intel_plane_y_copy_hw_state(struct intel_plane_state *y_plane_state,
> +					const struct intel_plane_state *uv_plane_state)
>  {
> -	intel_plane_clear_hw_state(plane_state);
> -
> -	memcpy(&plane_state->hw, &from_plane_state->hw,
> -	       sizeof(plane_state->hw));
> -
> -	if (plane_state->hw.fb)
> -		drm_framebuffer_get(plane_state->hw.fb);
> +	intel_plane_clear_hw_state(y_plane_state);
> +
> +	y_plane_state->hw.crtc		= uv_plane_state->hw.crtc;
> +	y_plane_state->hw.fb		= uv_plane_state->hw.fb;
> +	if (y_plane_state->hw.fb)
> +		drm_framebuffer_get(y_plane_state->hw.fb);
> +
> +	y_plane_state->hw.alpha		= uv_plane_state->hw.alpha;
> +	y_plane_state->hw.pixel_blend_mode = uv_plane_state->hw.pixel_blend_mode;
> +	y_plane_state->hw.rotation	= uv_plane_state->hw.rotation;
> +	y_plane_state->hw.color_encoding = uv_plane_state->hw.color_encoding;
> +	y_plane_state->hw.color_range	= uv_plane_state->hw.color_range;
> +	y_plane_state->hw.scaling_filter = uv_plane_state->hw.scaling_filter;

Please drop the extra spaces before ='s.

BR,
Jani.

>  }
>  
>  static void unlink_nv12_plane(struct intel_crtc_state *crtc_state,
> @@ -1549,7 +1555,7 @@ static void link_nv12_planes(struct intel_crtc_state *crtc_state,
>  	crtc_state->rel_data_rate[y_plane->id] = crtc_state->rel_data_rate_y[uv_plane->id];
>  
>  	/* Copy parameters to Y plane */
> -	intel_plane_copy_hw_state(y_plane_state, uv_plane_state);
> +	intel_plane_y_copy_hw_state(y_plane_state, uv_plane_state);
>  	y_plane_state->uapi.src = uv_plane_state->uapi.src;
>  	y_plane_state->uapi.dst = uv_plane_state->uapi.dst;
>  
> diff --git a/drivers/gpu/drm/i915/display/intel_plane.h b/drivers/gpu/drm/i915/display/intel_plane.h
> index 9d627d321f2e..a5bb0caa54a1 100644
> --- a/drivers/gpu/drm/i915/display/intel_plane.h
> +++ b/drivers/gpu/drm/i915/display/intel_plane.h
> @@ -39,8 +39,6 @@ void intel_plane_copy_uapi_to_hw_state(struct intel_atomic_state *state,
>  				       struct intel_plane_state *plane_state,
>  				       const struct intel_plane_state *from_plane_state,
>  				       struct intel_crtc *crtc);
> -void intel_plane_copy_hw_state(struct intel_plane_state *plane_state,
> -			       const struct intel_plane_state *from_plane_state);
>  void intel_plane_async_flip(struct intel_dsb *dsb,
>  			    struct intel_plane *plane,
>  			    const struct intel_crtc_state *crtc_state,

-- 
Jani Nikula, Intel