Display notch support

[Caleb Connolly]

On 28/04/2021 8:21 am, Simon Ser wrote:
>> A solution to make this configuration generic and exposed by the kernel
>> would standardise this across Linux
> Having a KMS property for this makes sense to me.
>
> Chatting with Jani on IRC, it doesn't seem like there's any EDID or
> DisplayID block for this.
>
> Note, Android exposes a data structure [1] with:
>
> - Margin of the cut-out for each edge of the screen
> - One rectangle per edge describing the cut-out region
> - Size of the curved area for each edge of a waterfall display
>
> I haven't found anything describing the rounded corners of the display.
>
> [1]: https://developer.android.com/reference/android/view/DisplayCutout

It looks like rounded corners only get a developer facing API in Android 
12 [1].

However from a vendor perspective it's possible to set padding for 
rounded corners [2], although this seems to mostly be a hack.

It seems like it would make sense to deal with cutouts and rounded 
corners separately, cutouts are always convex where rounded corners are 
always concave, they have different implications on how content should 
be adjusted.

[1]: 
https://developer.android.com/about/versions/12/features#rounded_corner_apis

[2]: 
https://github.com/LineageOS/android_device_oneplus_enchilada/commit/923c86a13b5ffb58683206a73a0813783e71e3fb