[Intel-gfx] [PATCH] drm/i915: Unpin vma iomapping when fbdev is destroyed

[Tvrtko Ursulin]

On 04/07/2017 11:17, Chris Wilson wrote:
> Quoting Tvrtko Ursulin (2017-07-04 10:46:40)
>> From: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
>>
>> If we don't release the iomapping we are not able to unpin the
>> vma which then gets leaked.
> 
> Oh, we still do unpin the vma on closing the object and we don't hold
> any extra object reference for the iomap. It is still a good patch for
> the symmetry, except it doesn't do what you say :-)

What do you mean that we don't hold any extra reference for the iomap? I 
see i915_vma_pin_iomap -> __i915_vma_pin -> vma->flags++. I can't spot 
the place which would override this and still unbind it at some point.

>> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
>> Cc: Chris Wilson <chris at chris-wilson.co.uk>
>> ---
>> Some time last year we talked about a pending patch to get rid
>> of the fbdev VMA leak. I lost track of what happened with that.
> 
> That was fixed by the intel_unpin_fb_vma() in there.

I suppose I don't see how since I don't see what defeats the elevated 
pin count from the above.

Regards,

Tvrtko