[Lima] [Mesa-dev] Question about EGL_KHR_partial_update implementation

[Emil Velikov]

Hi Frank,

On 28 June 2018 at 11:12, Frank Binns <frank.binns at imgtec.com> wrote:
> Hi Qiang,
>
> Qiang Yu <yuq825 at gmail.com> writes:
>
>> Hi Harish,
>>
>> I want to implement EGL_KHR_partial_update for lima mesa driver and find you
>> worked on Android/Wayland support for it:
>> https://patchwork.freedesktop.org/patch/160944/
>> https://patchwork.freedesktop.org/patch/188695/
>>
>> So I have some question about it:
>> your implementation seems to depend on platform (Android, wayland) support,
>> for example call native_window_set_surface_damage() in Android implementation.
>> What's the purpose of it, tell the Android SurfaceFlinger to redraw the damage
>> region? And is this damage region the "surface damage" or "buffer
>> damage" metioned
>> in the EGL_KHR_partial_update?
>> https://www.khronos.org/registry/EGL/extensions/KHR/EGL_KHR_partial_update.txt
>>
>> To my understand this extension should only depend on the driver support instead
>> of platform support while the EGL_KHR_swap_buffers_with_damage is the opposite:
>> https://www.khronos.org/registry/EGL/extensions/KHR/EGL_KHR_swap_buffers_with_damage.txt
>>
>
> I came across this too and I agree with you. I think the current
> implementation is incorrect and it should actually be passing the damage
> rectangles to the driver.
>
You're spot on - it was a point raised by Eric and me during the
original review.
The extension was tested on Intel hardware, a non-tiled one, hence the
implementation was a good starting point.

Admittedly a driver callback, providing greater flexibility would be good move.

HTH
Emil