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

From: Ville Syrjälä
Date: Thu Aug 11 2016 - 03:44:33 EST


On Thu, Aug 11, 2016 at 09:32:59AM +0200, Philipp Zabel wrote:
> 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);

BTW that looks wrong (already in the original). AFAICS the patch just
handled the gamma_lut, not the degamma_lut, so telling you have both
is not right.

>
> (See https://patchwork.kernel.org/patch/9160987/)
>
> regards
> Philipp
>
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--
Ville Syrjälä
Intel OTC