Re: [PATCH 1/7] drm/i915: Fix the offset issue for the stolen GEM objects

Chris Wilson
2014-01-09T09:45:25Z

On Thu, Jan 09, 2014 at 11:00:17AM +0530, akash.goel@intel.com wrote:
> From: Akash Goel <akash.goel@intel.com>
>
> The 'offset' field of the 'scatterlist' structure was wrongly
> programmed with the offset value from the base of stolen area,
> whereas this field indicates the offset from where the interested
> data starts within the PAGE pointed to by the 'page-link' field.
> As a result when a new GEM object allocated from the stolen
> area is mapped to GTT, it could lead to an overwrite of GTT entries
> as the page count calculation will go wrong, refer the function
> 'sg_page_count'.

This statement is incorrect since my use of sg here predates
sg_page_iter.

The stolen sg has no page_link, the meaning of offset/length here are
relative to the base of the stolen area.

However, if you wish to rephrase the above...
-Chris

--
Chris Wilson, Intel Open Source Technology Centre