On Tue, Jun 17, 2025 at 05:33:20AM +0000, Borah, Chaitanya Kumar wrote: > > > > -----Original Message----- > > From: Pekka Paalanen <[email protected]> > > Sent: Monday, June 16, 2025 7:02 PM > > To: Borah, Chaitanya Kumar <[email protected]> > > Cc: Alex Hung <[email protected]>; [email protected]; amd- > > [email protected]; [email protected]; > > [email protected]; [email protected]; [email protected]; > > [email protected]; [email protected]; [email protected]; > > [email protected]; [email protected]; [email protected]; > > [email protected]; [email protected]; [email protected]; > > [email protected]; [email protected]; Shankar, Uma > > <[email protected]>; [email protected]; > > [email protected]; [email protected]; [email protected]; > > [email protected]; [email protected]; > > [email protected]; Daniel Stone <[email protected]> > > Subject: Re: [PATCH V9 16/43] drm/colorop: Add 3x4 CTM type > > > > On Mon, 16 Jun 2025 11:30:23 +0000 > > "Borah, Chaitanya Kumar" <[email protected]> wrote: > > > > > > -----Original Message----- > > > > From: Alex Hung <[email protected]> > > > > Sent: Wednesday, April 30, 2025 6:41 AM > > > > To: [email protected]; [email protected] > > > > Cc: [email protected]; [email protected]; > > > > [email protected]; [email protected]; [email protected]; > > > > [email protected]; [email protected]; [email protected]; > > > > [email protected]; [email protected]; > > > > [email protected]; [email protected]; [email protected]; > > > > [email protected]; [email protected]; [email protected]; > > > > [email protected]; [email protected]; Shankar, Uma > > > > <[email protected]>; [email protected]; > > > > [email protected]; [email protected]; > > > > [email protected]; [email protected]; [email protected]; > > > > Borah, Chaitanya Kumar <[email protected]>; > > > > [email protected]; Daniel Stone <[email protected]> > > > > Subject: [PATCH V9 16/43] drm/colorop: Add 3x4 CTM type > > > > > > > > From: Harry Wentland <[email protected]> > > > > > > > > This type is used to support a 3x4 matrix in colorops. A 3x4 matrix > > > > uses the last column as a "bias" column. Some HW exposes support for > > > > 3x4. The calculation looks like: > > > > > > > > out matrix in > > > > |R| |0 1 2 3 | | R | > > > > |G| = |4 5 6 7 | x | G | > > > > |B| |8 9 10 11| | B | > > > > |1.0| > > > > > > > > This is also the first colorop where we need a blob property to > > > > program the property. For that we'll introduce a new DATA property > > > > that can be used by all colorop TYPEs requiring a blob. The way a > > > > DATA blob is read depends on the TYPE of the colorop. > > > > > > > > We only create the DATA property for property types that need it. > > > > > > Is there any value to adding pre-offsets [1] in the uapi? > > > > > > |R/Cr| | c0 c1 c2 | ( |R/Cr| |preoff0| ) |postoff0| > > > |G/Y | = | c3 c4 c5 | x ( |G/Y | + |preoff1| ) + |postoff1| > > > |B/Cb| | c6 c7 c8 | ( |B/Cb| |preoff2| ) |postoff2| > > > > > > Handling limited range values is one use case that I can think of. > > > > Hi, > > > > in the mathematical sense, no. A pre-offset can always be converted into a > > post-offset by multiplying it with the 3x3 matrix (and adding to the > > existing > > post-offset). This can be pre-computed, no need to do it separately for > > every > > pixel. > > > > For hardware reasons, I have no idea. > > Thank you for the reply, Pekka. Our hardware does allow programming > Pre-offsets separately. > Currently I can't think of a particular advantage of that if mathematically a > post-offset does the job but I will keep this thread posted if I find > something out.
Just FYI we have three different kinds of hardware: - 3x3 matrix - 3x3 matrix + programmable pre offsets + hardcoded post offsets for limited range conversion - 3x3 matrix + programmable pre and post offsets -- Ville Syrjälä Intel
