Re: [PATCH v3 3/5] drm/amd/display: use a separate helper to translate degamma curves

On 01/08/2026 03:41, Alex Hung wrote:
> I tested above on
>  - DCN35 - issue fiexed
>  - DCN401 - no issue and no regression.
>
> Does it pass DCN321 that you mentioned abouve?

Yes, with this change the kms_colorop passes on DCN321 and so far I 
don't see any visual regression on games.

I also checked that DCN2+ uses different CM helpers for degamma and 
gamma as well - but with 12 segments, which is the original distribution 
of _translate_curve_to_degamma_hw_format.
Just to say that the proposed approach isn't new.

>
> DCN301 doesn't use cm3_helper_translate_curve_to_degamma_hw_format() 
> so it wasn't affected.

Oh my, I wasn't expecting that! Banding was affecting both DCN301 and 
DCN321.
It was my fault, I overlooked DCN301, I'll extend the fix when we agree 
in the proper fix after Harry's review.

Thanks for the feedback,

Melissa

>
> The changes look good to me, but let's ask @Wentland, Harry for review 
> too.