Re: [PATCH v7 04/23] dt-bindings: display: mediatek: padding: Add MT8188

[Daniel Stone]

Hi Shawn,

On Mon, 16 Oct 2023 at 06:23, Shawn Sung (宋孝謙) <Shawn.Sung@xxxxxxxxxxxx> wrote:
> On Fri, 2023-10-13 at 17:26 +0100, Daniel Stone wrote:
> > If I understand the driver correctly, padding is automatically
> > applied
> > to compensate for unaligned dimensions. The first/last rows/columns
> > of
> > the overlay area will be filled with a specified colour (black?) to
> > preserve the area. This is unfortunately not OK to do transparently.
> > Userspace must be aware of this policy decision and specifically
> > request it. If not, the atomic request check should fail and tell
> > userspace that the requested configuration is not possible to
> > achieve.
>
> Yes, Padding works as you described, users can assign background colors
> for the filled area in 10bit RGB format, however, the rows and columns
> that are filled by Padding will be cropped by the hardware components
> after it to avoid situations as you mentioned, so users should not
> notice any difference.

Thanks for the explanation, I hadn't realised that the added padding
later gets cropped.

Cheers,
Daniel