[igt-dev] [PATCH i-g-t] lib/i915/gem_mman: Add support for GEM_MMAP_OFFSET ioctl

[Chris Wilson]

Quoting Zbigniew Kempczyński (2019-12-05 12:31:13)
> With introduction of new kernel ioctl we need to cover this in
> the IGT's. Patch adds mmap functions appropriate for this.
> 
> Signed-off-by: Lukasz Kalamarz <lukasz.kalamarz at intel.com>
> Signed-off-by: Antonio Argenziano <antonio.argenziano at intel.com>
> Signed-off-by: Zbigniew Kempczyński <zbigniew.kempczynski at intel.com>
> Cc: Chris Wilson <chris at chris-wilson.co.uk>

Do we really have people outside of gem_mmap_wc.c and gem_mmap_offset.c
that care whether their WC/WB mmapping is provided by MMAP_OFFSET_IOCTL
or MMAP_IOCTL. They just expect it to work, I would have thought --
basically just gem_mmap__device_coherent (and maybe the alternative would
be gem_mmap__cache_coherent, don't quote me on that :)

It's not a huge deal, I think it falls under overengineering that will
simply lead to confusion of "when do I use one and not the other?"

Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
-Chris