[igt-dev] [PATCH i-g-t] tests/gem_render_copy: Add software tiling / detiling support

[Chris Wilson]

Quoting Zbigniew Kempczyński (2019-11-29 09:36:53)
> Older GENs have mmapable GGTT which does buffer tiling / detaling
> automatically. Newer GENs have looses this possibility so software
> tiling / detiling is required.

A bunch of trivial checks to ensure idempotence (i.e linear -> X ->
linear) with 4K and 2M and a bunch of tiling strides would be useful.

Note that these functions only correspond to HW detiling when swizzling
is off -- you can ask the kernel via GET_TILING_IOCTL.
-Chris