FW: [PATCH v2 2/2] drm/amdgpu: Move to gtt before cpu accesses dma buf.

Michel Dänzer michel at daenzer.net
Thu Dec 14 16:16:00 UTC 2017

On 2017-12-14 09:07 AM, Christian König wrote:
> Please CC Michel as well,

No need, I read the lists (just sometimes get a little swamped and take
time to catch up).

> he originally commented that we should try to solve this in the DDX instead.

I don't think a DDX driver is even involved in the scenario Sam's
working on.

Do you mean that the BO should be created in GTT in the first place if
possible? I did suggest that before, but I'm not sure it's feasible in
this scenario.

> And BTW: Why don't we just do the migration during the mmap call?

At mmap time, we don't know when the BO will actually be accessed by the
CPU (or indeed whether at all). If we do the migration at that point,
there's no guarantee that the BO will still be in GTT when it's accessed
by the CPU.

Earthling Michel Dänzer               |               http://www.amd.com
Libre software enthusiast             |             Mesa and X developer

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