[Intel-gfx] [PATCH] Revert "drm/i915: Disallow pin ioctl completely for kms drivers"

[Chris Wilson]

On Thu, Nov 27, 2014 at 03:56:38PM +0200, Jani Nikula wrote:
> On Tue, 25 Nov 2014, Chris Wilson <chris at chris-wilson.co.uk> wrote:
> > This reverts commit c211a47c2c28562f8a3fff9e027be1a3ed9e154a.
> >
> > This causes an unwarranteed API break for existing and active userspace.
> 
> Ville had an interesting observation regarding the commit being
> reverted: https://bugs.freedesktop.org/show_bug.cgi?id=86679#c9

Not really, it is just a hack to workaround the equally gross hack

commit d23db88c3ab233daed18709e3a24d6c95344117f
Author: Chris Wilson <chris at chris-wilson.co.uk>
Date:   Fri May 23 08:48:08 2014 +0200

    drm/i915: Prevent negative relocation deltas from wrapping

which is to work around a hw bug on gen7+.

The fix would have either to been to also observe the bias inside
pin_ioctl.
-Chris
 

-- 
Chris Wilson, Intel Open Source Technology Centre