[PATCH] drm/i915/color: Use correct variable to load lut

[Kandpal, Suraj]

> -----Original Message-----
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> Sent: Wednesday, October 9, 2024 12:25 PM
> To: Kandpal, Suraj <suraj.kandpal at intel.com>
> Cc: intel-xe at lists.freedesktop.org; intel-gfx at lists.freedesktop.org; Shankar,
> Uma <uma.shankar at intel.com>; Borah, Chaitanya Kumar
> <chaitanya.kumar.borah at intel.com>
> Subject: Re: [PATCH] drm/i915/color: Use correct variable to load lut
> 
> On Wed, Oct 09, 2024 at 12:07:53PM +0530, Suraj Kandpal wrote:
> > Use the blob variable instead of post_csc_lut as it may end up being
> > null.
> 
> Not possible. We always have a LUT for each half in split gamma mode, and
> if we don't then someone screwed up much earlier before we end up here.
> 

If that is the case then the code line
const struct drm_property_blob *blob = post_csc_lut ?: pre_csc_lut;
wouldn't be needed but it has been added  presumably because there are times
that we reach here with post csc as null and in that case we at least make sure we are
loading the correct lut hence the fix.

Regards,
Suraj Kandpal

> >
> > Signed-off-by: Suraj Kandpal <suraj.kandpal at intel.com>
> > ---
> >  drivers/gpu/drm/i915/display/intel_color.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_color.c
> > b/drivers/gpu/drm/i915/display/intel_color.c
> > index caf1af039960..22b7090c4f6f 100644
> > --- a/drivers/gpu/drm/i915/display/intel_color.c
> > +++ b/drivers/gpu/drm/i915/display/intel_color.c
> > @@ -1503,7 +1503,7 @@ static void ivb_load_luts(const struct
> intel_crtc_state *crtc_state)
> >  		ivb_load_lut_10(crtc_state, pre_csc_lut,
> PAL_PREC_SPLIT_MODE |
> >  				PAL_PREC_INDEX_VALUE(0));
> >  		ivb_load_lut_ext_max(crtc_state);
> > -		ivb_load_lut_10(crtc_state, post_csc_lut,
> PAL_PREC_SPLIT_MODE |
> > +		ivb_load_lut_10(crtc_state, blob, PAL_PREC_SPLIT_MODE |
> >  				PAL_PREC_INDEX_VALUE(512));
> >  		break;
> >  	case GAMMA_MODE_MODE_10BIT:
> > @@ -1531,7 +1531,7 @@ static void bdw_load_luts(const struct
> intel_crtc_state *crtc_state)
> >  		bdw_load_lut_10(crtc_state, pre_csc_lut,
> PAL_PREC_SPLIT_MODE |
> >  				PAL_PREC_INDEX_VALUE(0));
> >  		ivb_load_lut_ext_max(crtc_state);
> > -		bdw_load_lut_10(crtc_state, post_csc_lut,
> PAL_PREC_SPLIT_MODE |
> > +		bdw_load_lut_10(crtc_state, blob, PAL_PREC_SPLIT_MODE |
> >  				PAL_PREC_INDEX_VALUE(512));
> >  		break;
> >  	case GAMMA_MODE_MODE_10BIT:
> > --
> > 2.43.2
> 
> --
> Ville Syrjälä
> Intel