[Intel-gfx] [PATCH] drm/i915: Remove incorrect warning in context cleanup

[Chris Wilson]

On Tue, Nov 24, 2015 at 11:58:22AM +0100, Daniel Vetter wrote:
> On Fri, Nov 20, 2015 at 01:23:36PM +0000, Tvrtko Ursulin wrote:
> > From: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> > 
> > Commit e9f24d5fb7cf3628b195b18ff3ac4e37937ceeae
> > Author: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> > Date:   Mon Oct 5 13:26:36 2015 +0100
> > 
> >     drm/i915: Clean up associated VMAs on context destruction
> > 
> > Added a warning based on an incorrect assumption that all VMAs
> > in a VM will be on the inactive list at the point last reference
> > to a context and VM is dropped.
> > 
> > This is not true because i915_gem_object_retire__read will not
> > put VMA on the inactive list until all activities on the object
> > in question (in all VMs) have been retired.
> > 
> > As a consequence, whether or not a context/VM will be destroyed
> > with its VMAs still on the active list, can depend on completely
> > unrelated activities using the same object from a different
> > context or engine.
> > 
> > Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=92638
> > Testcase: igt/gem_request_retire/retire-vma-not-inactive
> > Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
> > Cc: Chris Wilson <chris at chris-wilson.co.uk>
> > Cc: Michel Thierry <michel.thierry at intel.com>
> 
> Queued for -next, thanks for the patch.

The WARN_ON is accurate though. The original patch fails to fix even the
limited aspect of the bug it claimed to.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre