[PATCHv2] etnaviv: Add support for ETC2 texture compression

[Wladimir J. van der Laan]

> I can confirm that 11 bit stuff works on the GC2000 . I used piglit's
> oes_compressed_etc2_texture-miptree_gles3 for verification.
> How have you tested these formats?

I rendered the example images from
https://github.com/Ericsson/ETCPACK/tree/master/testing/testvectors_correct/pkm,
which displayed fine, both the 11 and 8 bit variants.

Haven't checked pixel-for-pixel though.

Wladimir

> 
> For instance I get the following fails:
> debian at cubox:~/ac_mesa$
> /home/debian/piglit/bin/oes_compressed_etc2_texture-miptree_gles3 rgb8
> -auto -fbo
> Probe color at (16,0)
>   Left: 0.533333 0.200000 0.000000 1.000000
>   Right: 0.866667 0.600000 0.333333 1.000000
> PIGLIT: {"result": "fail" }
> debian at cubox:~/ac_mesa$
> /home/debian/piglit/bin/oes_compressed_etc2_texture-miptree_gles3
> rgb8-punchthrough-alpha1 -auto -fbo
> Probe color at (6,0)
>   Left: 0.733333 0.400000 0.000000 1.000000
>   Right: 0.133333 0.066667 0.000000 1.000000
> PIGLIT: {"result": "fail" }
> 
> With that fact I think we need to find out what is broken with the non
> 11 bit formats on GC2000 and if everything works on your platform. I
> am not
> sure if we should advertise the broken formats (on gpus with HALTI0).
> 
> greets
> --
> Christian Gmeiner, MSc
> 
> https://www.youtube.com/user/AloryOFFICIAL
> https://soundcloud.com/christian-gmeiner