On Mon, Nov 20, 2023 at 01:17:05PM +0000, Borah, Chaitanya Kumar wrote: > > > > -----Original Message----- > > From: Borah, Chaitanya Kumar > > Sent: Monday, November 20, 2023 6:33 PM > > To: Ville Syrjälä <[email protected]> > > Cc: [email protected]; [email protected]; Jani > > Nikula <[email protected]> > > Subject: RE: [Intel-gfx] [PATCH 1/4] drm: Fix color LUT rounding > > > > Hello Ville, > > > > > -----Original Message----- > > > From: dri-devel <[email protected]> On Behalf Of > > > Ville Syrjälä > > > Sent: Tuesday, October 31, 2023 9:37 PM > > > To: Jani Nikula <[email protected]> > > > Cc: [email protected]; [email protected] > > > Subject: Re: [Intel-gfx] [PATCH 1/4] drm: Fix color LUT rounding > > > > > > On Tue, Oct 31, 2023 at 11:15:35AM +0200, Jani Nikula wrote: > > > > On Fri, 13 Oct 2023, Ville Syrjala <[email protected]> > > > > wrote: > > > > > entrirely. But perhaps a better idea would be to follow the OpenGL > > > > > int<->float conversion rules, in which case we get the following > > > > > results: > > > > > > > > Do you have a pointer to the rules handy, I couldn't find it. :( > > > > > > Eg. '2.3.5 Fixed-Point Data Conversions' in GL 4.6 spec. The section > > > number probably changes depending on which version of the spec you look > > at. > > > > > > > This section particularly talks about conversion of normalized fixed point > > to > > floating point numbers and vice versa. > > Pardon my limited knowledge on the topic but aren't we just doing a scaling > > factor conversion(Q0.16 -> Q0.8) in these patches? > > > > I could not draw a direct relation between the formulas in the section[1] > > and > > what we are doing here.(but it could be just me!) > > Scratch that! As I understand, in effect we are doing a Q0.16 Fixed Point -> > Floating point -> Q0.8 Fixed Point conversion.
Yep, that's it. > Correct me if I am wrong! Otherwise > > LGTM. > > Reviewed-by: Chaitanya Kumar Borah <[email protected]> > > > > > > Regards > > > > Chaitanya > > > > [1] https://registry.khronos.org/OpenGL/specs/gl/glspec46.core.pdf '2.3.5 > > Fixed-Point Data Conversions' > > > > > > > > > > Might also add the reference to the commit message and/or comment. > > > > > > > > BR, > > > > Jani. > > > > > > > > -- > > > > Jani Nikula, Intel > > > > > > -- > > > Ville Syrjälä > > > Intel -- Ville Syrjälä Intel
