Re: [PATCH v4 3/4] drm/mediatek: Add gamma correction.

[Philipp Zabel]

Am Donnerstag, den 28.07.2016, 10:22 +0800 schrieb Bibby Hsieh:
> Add gamma set function to correct brightness values.
> It applies arbitrary mapping curve to compensate the
> incorrect transfer function of the panel.
> 
> Signed-off-by: Bibby Hsieh <bibby.hsieh@xxxxxxxxxxxx>
> ---
>  drivers/gpu/drm/mediatek/mtk_drm_crtc.c     |    8 ++++++-
>  drivers/gpu/drm/mediatek/mtk_drm_crtc.h     |    1 +
>  drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c |   31 +++++++++++++++++++++++++++
>  drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.h |   10 +++++++++
>  4 files changed, 49 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> index 24aa3ba..cbb460a5 100644
> --- a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> +++ b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> @@ -409,6 +409,9 @@ static void mtk_drm_crtc_atomic_flush(struct drm_crtc *crtc,
>  	}
>  	if (pending_planes)
>  		mtk_crtc->pending_planes = true;
> +	if (crtc->state->color_mgmt_changed)
> +		for (i = 0; i < mtk_crtc->ddp_comp_nr; i++)
> +			mtk_ddp_gamma_set(mtk_crtc->ddp_comp[i], crtc->state);
>  }
>  
>  static const struct drm_crtc_funcs mtk_crtc_funcs = {
> @@ -418,6 +421,7 @@ static const struct drm_crtc_funcs mtk_crtc_funcs = {
>  	.reset			= mtk_drm_crtc_reset,
>  	.atomic_duplicate_state	= mtk_drm_crtc_duplicate_state,
>  	.atomic_destroy_state	= mtk_drm_crtc_destroy_state,
> +	.gamma_set		= drm_atomic_helper_legacy_gamma_set,
>  };
>  
>  static const struct drm_crtc_helper_funcs mtk_crtc_helper_funcs = {
> @@ -568,7 +572,9 @@ int mtk_drm_crtc_create(struct drm_device *drm_dev,
>  				&mtk_crtc->planes[1].base, pipe);
>  	if (ret < 0)
>  		goto unprepare;
> -
> +	drm_mode_crtc_set_gamma_size(&mtk_crtc->base, MTK_LUT_SIZE);
> +	drm_helper_crtc_enable_color_mgmt(&mtk_crtc->base, MTK_LUT_SIZE,
> +					  MTK_LUT_SIZE);

I have applied all four patches and rebased onto v4.8-rc1, replacing
drm_helper_crtc_enable_color_mgmt with:

	drm_crtc_enable_color_mgmt(&mtk_crtc->base, MTK_LUT_SIZE,
				   true, MTK_LUT_SIZE);

(See https://patchwork.kernel.org/patch/9160987/)

regards
Philipp