Re: [Freedreno] [PATCH v2 04/17] drm/msm/dpu: Fix PP_BLK_DIPHER -> DITHER typo

[Abhinav Kumar]

On 4/25/2023 2:53 PM, Marijn Suijten wrote:
> On 2023-04-25 14:37:21, Abhinav Kumar wrote:
> > On 4/25/2023 1:43 PM, Marijn Suijten wrote:
> > > On 2023-04-25 09:47:30, Abhinav Kumar wrote:
> > > > On 4/25/2023 9:33 AM, Marijn Suijten wrote:
> > > > > On 2023-04-25 09:18:58, Abhinav Kumar wrote:
> > > > > > On 4/24/2023 11:54 PM, Marijn Suijten wrote:
> > > > > > > On 2023-04-24 16:09:45, Abhinav Kumar wrote:
> > > > > > > <snip>
> > > > > > > > > > dither block should be present on many other chipsets too but looks like
> > > > > > > > > > on sm8550 was enabling it. Not sure how it was validated there. But we
> > > > > > > > > > are enabling dither, even other chipsets have this block.
> > > > > > > > >
> > > > > > > > > Correct, they all seem to have it starting at sdm845.  My patch message
> > > > > > > > > seems to lack the word "exclusively" as the PP on sm8550 appears to
> > > > > > > > > exclusively contain a DITHER subblock (unless other blocks are available
> > > > > > > > > that simply aren't supported within this driver yet) and no other
> > > > > > > > > registers.  Hence this aptly named macro exist to emit just the feature
> > > > > > > > > bitflag for that and a .len of zero.
> > > > > > > >
> > > > > > > > I think after the TE blocks were moved to INTF, dither is the only
> > > > > > > > sub-block for all Ping-Pongs not just in sm8550.
> > > > > > >
> > > > > > > So you are asking / leaving context to make all >= 5.0.0 pingpong blocks
> > > > > > > use this macro with only a single DITHER sblk in PP?
> > > > > > >
> > > > > > > As far as I recall SM8550 is the first SoC to use zero registers in PP,
> > > > > > > which is specifically what this macro takes care of too.  Then, there
> > > > > > > are only a few SoCs downstream still (erroneously?) referencing TE2 as
> > > > > > > the only other sub-blk, those SoCs still use sdm845_pp_sblk_te.
> > > > > >
> > > > > > So, what I didnt follow is why should sm8450 use PP_BLK_TE Vs sm8550
> > > > > > should use PP_BLK_DIPHER?
> > > > > >
> > > > > > Atleast for those two, both should be using PP_BLK_DIPHER.
> > > > > >
> > > > > > Thats what I was trying to note here.
> > > > > >
> > > > > > This isnt even right as there is no PP_BLK_TE in sm8450.
> > > > >
> > > > > SM8450 doesn't use PP_BLK_TE (TE2) anymore since the second patch in
> > > > > this series.  If you think it should use the DITHER (not DIPHER!) macro
> > > > > instead of the regular PP_BLK with a size of 0xd4, we can do that in
> > > > > another patch as that's not strictly related to this series.
> > > >
> > > > Yes, thanks for pointing the TE2 was removed in the prev patch of this
> > > > series for sm8450. I was just focusing too much on this patch.
> > > >
> > > > And Yes, I think we should use the DIPHER ..... oh sorry .... DITHER ;)
> > > >
> > > > Yes, it can go as a different series, like I already wrote many times in
> > > > this.
> > >
> > > Thanks, that'd be great.  I wasn't sure at this point what you wanted to
> > > be changed here, after commenting on a typo fix rather than i.e. patch 2
> > > that deals with the TE2 sub-block of PP :)
> >
> > The reason I commented on this patch is because all the discussion so
> > far was surrounding the PP_BLK_DITHER macro which was being touched in
> > this patch.
> >
> > So even now, we found out about sm8450 and sm8550 because of the
> > question that why sm8550 alone should use PP_BLK_DITHER and not sm8450.
> >
> > This patch led to all the discussion about PP_BLK_DITHER.
> >
> > Even though it was just a typo fix patch, it uncovered deeper issues in
> > catalog about why PP_BLK_DITHER wasnt used more often.
>
> Indeed: the initial question was for the dither _block_ which is enabled
> on every other platform, just through the original macros which do more
> than exclusively enabling the dither block.
>
> > > > But atleast now, someone will remember to do it.
>
> I'll see whether I can include these fixes before sending v3 (got all
> the other changes in and am all-ready to send it): is there any other
> SoC you're seeing this issue on?

Thats alright, you can have it in a separate series not v3 of this one.

I am picking up the fixes from this one now.

I will update the other SOCs on IRC or even better i will take up this 
cleanup.

> - Marijn
>
> > > > > Note that that's the only difference between these macros.  The size
> > > > > becomes 0 but the .features mask is the same (SM8450 uses
> > > > > PINGPONG_SM8150_MASK).
> > > > >
> > > > > These patches are anyway already distracting from my series, but were
> > > > > easier to do in one go as I was touching the PP and INTF catalog blocks
> > > > > regardless.
> > > > >
> > > > > While at it, perhaps we should check if the version and offset for the
> > > > > DITHER block are correct?  SM8450 uses SDM845 sblk definitions.
> > > >
> > > > Yes I already checked. the version and offset of dither are same between
> > > > sm8450 and sm8550.
> > >
> > > Thanks for checking, so then sm8450 is wrong on multiple occasions.
> > > Let's check all other SoCs that use sdm845_pp_sblk whether they should
> > > have used sc7280_pp_sblk instead.
> > >
> > > - Marijn