[Intel-gfx] [PATCH] drm/i915: Pin tiled objects for L-shaped configs

[Chris Wilson]

On Tue, Apr 07, 2015 at 10:05:39AM +0200, Daniel Vetter wrote:
> On Fri, Apr 03, 2015 at 10:43:29AM +0100, Chris Wilson wrote:
> > I resurrected my dual-channel evenly loaded gm45 and to my surprise
> > found it reporting a L-shaped memory layout.
> 
> Well my gm45 is also dual-channel and evenly loaded and still mangles
> tiled buffers when going through swap. Is gem_tiled_swapping happy on your
> box?

ickle at x200s ~/intel-gpu-tools/tests $ sudo ./gem_tiled_swapping 
IGT-Version: 1.10-ge809895 (x86_64) (Linux: 4.0.0-rc6+ x86_64)
Using 640 1MiB objects (available RAM: 343/3847, swap: 3989)
Subtest non-threaded: SUCCESS (23.344s)
Subtest threaded: SUCCESS (110.801s)

> > Perhaps the if ((ddc2 & DISABLE) == 0) is inverted or is not the truly
> > magic bit?
> 
> It was the best one I could find - given how old this all is now I think
> some false positives are acceptable in the test. I did try a few other
> things which did all fail.

It's the false-negative I worry about. I am just worried this is not the
bit we are looking for. Time will tell if we get a new bug report with
broken swizzling after swapping.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre