vaGetSurfaceBufferWl() is not implemented at VAAPI Gallium state tracker, which
prevents it's usage under Wayland.

But, after the DRI3 patches for hardware video decoding landed, NOT_IMPLEMENTED
return was removed, making the false sense what this will work under Wayland as
expected[1]. But it's still don't.

See the bug referenced under "See Also".

Also, I don't know actually, under which component should I file this bug. So
redirect me if I had mistaken.

[1]:
https://cgit.freedesktop.org/mesa/mesa/tree/src/gallium/state_trackers/va/context.c#n129