[Intel-gfx] [PATCH 5/5] drm/i915: Fix error capture on BYT/BDW

[Chris Wilson]

On Fri, Jan 24, 2014 at 06:17:45PM -0800, Ben Widawsky wrote:
> The previous check during error capture of whether or not the current VM
> should be scanned used, gen < 7. That was more or less trying to
> determine if there was a full PPGTT. At the time, this was sort of what
> I meant to do because I was more interested in working backwards from
> hardware state. However, this is incorrect because it will not include
> platforms that are greater than gen7, and not having PPGTT.  Example
> would be BYT which is gen7 but doesn't have PPGTT, BDW, or any platform
> greater than gen7 with the PPGTT module parameter invoked.
> 
> I am /assuming/ BYT was broken, I have not actually checked.
> 
> While here, clean up the file a bit to avoid duplicate reads (now that
> the PPGTT info is in the error state).
> 
> I think Mika/Chris may have been looking at this too.

Sure, we are looking (for identifying the guilty request/batch) by using
the older, simpler mechanism of finding the first incomplete request. I
think that search is now definite since we preallocate the request and no
longer do request collascing if ENOMEM (i.e. there is a 1:1 relationship
between seqno/batch/request).

That should also apply here and be much simpler.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre