[PATCH v2] drm/fourcc: add ARM GPU tile format

[Alyssa Rosenzweig]

> 1. Does AFBC_FORMAT_MOD_BLOCK_SIZE_16x16 without any
> AFBC_FORMAT_MOD_XXX uncompressed format just reorder the pixels
> in one 16x16 block same way as GPU "tiled" format? Or just no reorder (linear)?
> 
> 2. Is there any unreleased AFBC_FORMAT_MOD_XXX bit for this GPU
> "tiled" format?

I believe the answer to both is no, based on the parent email. The
uncompressed tiling scheme is older than AFBC, I think. Using the AFBC
modifiers for it doesn't make sense.

> 3. If the answer to 1&2 is no, seems Mali GPU formats and Mali Display
> formats are in different systems, do Mali Display guys agree to divide
> these two different format systems by the MSB bits of format field in this
> patch?

It's closer to "Mali GPU only formats" and "Everything else in the Mali
ecosystem"... Utgard-style tiling was GPU-specific. AFBC is Arm trying
to standardize across all their systems. Midgard+ can both render and
sample AFBC; the Mali video cores produce AFBC; the Mali display
processors consume AFBC; the Rockchip RK3399 display processor consumes
AFBC (I'm working on a patch to get that mainlined).

So upon further thought, I think this division makes sense.