[PATCH v5] rockchip/drm: vop2: add support for gamma LUT

[Daniel Stone]

Hi all,

On Wed, 16 Oct 2024 at 02:11, Andy Yan <andyshrk at 163.com> wrote:
> At 2024-10-16 04:13:40, "Piotr Zalewski" <pZ010001011111 at proton.me> wrote:
> >Ok I get it now. Is such rework correct? - when gamma LUT for rk356x is
> >being set, instead of disabling the LUT before the gamma LUT write for the
> >current CRTC's video port, active video port is selected. Selection is
> >based on if DSP LUT EN bit is set for particular video port. eg:
>
> If the userspace want to set gamma for CRTCx,  then that is indeed where they want to set the
> gamma on。The driver silently sets the gamma on another CRTC, which is not what the user wants.
>
> I think there are two options：
> （1）return a error if gamma is enable on other CRTC， this is what we done in our BSP code[1]
>   (2)  disable the dsp_lut on privious CRTC, then switch to the current CRTC which userspace wants.

1 is the only solution that can work. Silently changing the colour
properties of a separate CRTC is not OK, since this can lead to
displaying incorrect content.

Cheers,
Daniel