[Intel-gfx] [PATCH] drm/i915: Report the actual swizzling back to userspace

[Chris Wilson]

On Fri, Oct 24, 2014 at 04:39:29PM +0200, Daniel Vetter wrote:
> On Fri, Oct 24, 2014 at 12:11:11PM +0100, Chris Wilson wrote:
> > Userspace cares about whether or not swizzling depends on the page
> > address for its direct access into bound objects. Extend the get_tiling
> > ioctl to report the physical swizzling value in addition to the logical
> > swizzling value so that userspace can accurately determine when it is
> > possible for manual detiling.
> > 
> > Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> > Cc: Akash Goel <akash.goel at intel.com>
> > Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
> 
> I wonder whether we should care really, since on gen5+ we know that they
> agree. Pimp some igt (by skipping if needed) to convince me?

It's for gen2-4... Trivial little change to enable more sharing of code
paths and speedups.

What type of igt do you want? I personally have never seen a bit17
swizzling machine, but we know that some do exist due to the bug
reports.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre