(In reply to Alex Deucher from comment #3)

> 
> I guess there are 3 options:
> 
> 1. Force the option but limit it to cases where you are only using the
> output surface via the interop extension.  This works today.
> 2. Add an extra step to the drivers using shaders to split the frame up into
> separate fields in vlVdpVideoSurfaceGallium
> (src/gallium/state_trackers/vdpau/surface.c) for chips that don't support
> field based decode.  This adds an extra copy and someone needs to write the
> code.  With that done, the extension can be enabled on all asics.
> 3.  Write a new simplified GL/VDPAU interop extension that only supports
> interop with output surfaces.  This extension could be enabled on all asics.

I think option 1. is good enough. This is done by setting the environment
variable, right? We can force using the mixer if this variable is set.