Re: [PATCH 0/2] DPU1 GC1.8 wiring-up

[Dmitry Baryshkov]

On 20/04/2023 22:56, Marijn Suijten wrote:
> On 2023-04-20 22:51:22, Dmitry Baryshkov wrote:
> > On 20/04/2023 22:47, Abhinav Kumar wrote:
> > > On 4/20/2023 11:01 AM, Dmitry Baryshkov wrote:
> > > > On 20/04/2023 04:36, Konrad Dybcio wrote:
> > > > > On 20.04.2023 03:28, Abhinav Kumar wrote:
> > > > > > On 4/19/2023 6:26 PM, Konrad Dybcio wrote:
> > > > > > > On 20.04.2023 03:25, Dmitry Baryshkov wrote:
> > > > > > > > On 20/04/2023 04:14, Konrad Dybcio wrote:
> > > > > > > > > Almost all SoCs from SDM845 to SM8550 inclusive feature a GC1.8
> > > > > > > > > dspp sub-block in addition to PCCv4. The other block differ a bit
> > > > > > > > > more, but none of them are supported upstream.
> > > > > > > > >
> > > > > > > > > This series adds configures the GCv1.8 on all the relevant SoCs.
> > > > > > > >
> > > > > > > > Does this mean that we will see gamma_lut support soon?
> > > > > > > No promises, my plate is not even full, it's beyond overflowing! :P
> > > > > > >
> > > > > > > Konrad
> > > > > >
> > > > > > So I think I wrote about this before during the catalog rework/fixes
> > > > > > that the gc registers are not written to / programmed.
> > > > > >
> > > > > > If thats not done, is there any benefit to this series?
> > > > > Completeness and preparation for the code itself, if nothing else?
> > > >
> > > > The usual problem is that if something is not put to use, it quickly
> > > > rots or becomes misused for newer platforms. We have seen this with
> > > > the some of DPU features.
> > > >
> > > > In case of GC (and the freshly defined DPU_DSPP_IGC, but not used) we
> > > > have three options:
> > > > - drop the unused GC from msm8998_sblk.
> > > > - keep things as is, single unused GC entry
> > > > - fill all the sblk with the correct information in hope that it stays
> > > > correct
> > > >
> > > > Each of these options has its own drawbacks. I have slight bias
> > > > towards the last option, to have the information in place (as long as
> > > > it is accurate).
> > >
> > > My vote is for (1) . Today, GC is unused and from the discussion here,
> > > there is no concrete plan to add it. If we keep extending an unused
> > > bitmask for all the chipsets including the ones which will get added in
> > > the future in the hope that someday the feature comes, it doesnt sound
> > > like a good idea.
> > >
> > > I would rather do (1), if someone has time.
> >
> > Agree, this was the second item on my preference list. Could you please
> > send this oneliner?
>
> Nit (to make sure we're on the same thought here): I think it's a
> 3-liner: remove it from DSPP_MSM8998_MASK as well as msm8998_dspp_sblk.
>
> > > OR lets stay at (2) till
> > > someone does (1).
>
> I'm personally okay leaving it in place too, with an eye on implementing
> this, IGC, and other blocks at some point if there's a use for it via
> standard DRM properties.

I took a quick glance. I think it is possible, but not straightforward. 
But I must admit here, I don't have a full picture regarding different 
color encodings, ranges and the rest of gamma/degamma API and usage.

> > > When someone implements GC, we can re-use this patch and that time keep
> > > konrad's author rights or co-developed by.
>
> Good to at least know all these SoCs have the same offset and revision.
>
> - Marijn

--
With best wishes
Dmitry