[Mesa-dev] Question about EGL_KHR_partial_update implementation

[Qiang Yu]

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

For lima implementation, I want to use the damage region (buffer
damage) provided
by EGL_KHR_partial_update to skip rendering of un-damaged region when
eglSwapBuffersXXX. And tell damage region (surface damage) to compositor should
be left to eglSwapBuffersWithDamageKHR provided by
EGL_KHR_swap_buffers_with_damage.

Regards,
Qiang