[Intel-gfx] [PATCH 2/3] drm/i915: mark GEM objects as dirty when updated by the CPU

[Chris Wilson]

On Tue, Dec 08, 2015 at 04:51:17PM +0000, Dave Gordon wrote:
> In various places, one or more pages of a GEM object are mapped into CPU
> address space and updated. In each such case, either the page or the the
> object should be marked dirty, to ensure that the modifications are not
> discarded if the object is evicted under memory pressure.
> 
> Ideally, we would like to mark only the updated pages dirty; but it
> isn't clear at this point whether this will work for all types of GEM
> objects (regular/gtt, phys, stolen, userptr, dmabuf, ...). So for now,
> let's ensure correctness by marking the whole object dirty.
> 
> Signed-off-by: Dave Gordon <david.s.gordon at intel.com>
> Cc: Chris Wilson <chris at chris-wilson.co.uk>
> ---
>  drivers/gpu/drm/i915/i915_gem_execbuffer.c   | 2 ++
>  drivers/gpu/drm/i915/i915_gem_render_state.c | 1 +
>  drivers/gpu/drm/i915/i915_guc_submission.c   | 1 +
>  drivers/gpu/drm/i915/intel_lrc.c             | 6 +++++-
>  4 files changed, 9 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> index a4c243c..bc28a10 100644
> --- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> +++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> @@ -281,6 +281,7 @@ relocate_entry_cpu(struct drm_i915_gem_object *obj,
>  	}
>  
>  	kunmap_atomic(vaddr);
> +	obj->dirty = 1;
Nak. CPU dirtying is a per-page interface.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre