[Intel-gfx] [PATCH] drm/i915/guc: Fix a fw content lost issue after it is evicted

[Yu Dai]

On 11/06/2015 02:07 PM, Chris Wilson wrote:
> On Fri, Nov 06, 2015 at 01:55:27PM -0800, yu.dai at intel.com wrote:
> > From: Alex Dai <yu.dai at intel.com>
> >
> > We keep a copy of GuC fw in a GEM obj. However its content is lost
> > if the GEM obj is evicted (igt/gem_evict_*). Therefore, the later
> > fw loading during GPU reset will fail.
>
> No, it's not. The bug is in sg_copy_buffer called by
> i915_gem_object_create_from_data introduced by yourselves.
>

My understanding is that sg_copy_from_buffer is used to copy data. Can 
you clarify why using this will cause such issue? I also did another 
experiment that always leaving the GEM obj pinned, then it's content 
never changed.

Alex