[PATCH 1/3] drm/amdgpu: fix VA hole handling on Vega10 v2

Christian König ckoenig.leichtzumerken at gmail.com
Sat Nov 18 14:31:52 UTC 2017

Am 17.11.2017 um 17:09 schrieb Michel Dänzer:
> On 17/11/17 11:28 AM, Christian König wrote:
>> Ping? Michel, Alex can somebody take a look?
> Patch 2 is
> Reviewed-by: Michel Dänzer <michel.daenzer at amd.com>
> With patches 1 & 3, it's not 100% clear to me what the idea is behind
> the handling of the hole on the kernel and userspace side. Maybe you can
> add some explanation in code comments or the commit logs?
Yeah, that is actually a bit of a mess because the hardware 
documentation wasn't very clear on how this works.

How about this as extra code comment on patch 1 to the assignment of 

  * Old userspace isn't aware of the VA hole on Vega10. So in theory an 
client could get invalid VA addresses assigned.
  * To fix this and keep backward compatibility we limit the VA space 
reported in this field to the range below the hole.

The last patch is then to report the VA space above the hole, cause that 
is actually what libdrm should use.

The crux is when I put the VA space above the hole directly into the old 
fields older versions of libdrm would break and we can't do that.


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