[PATCH 14/25] drm/amdkfd: Populate DRM render device minor

[Felix Kuehling]

On 2018-02-14 03:50 AM, Michel Dänzer wrote:
> On 2018-02-13 08:18 PM, Felix Kuehling wrote:
>> On 2018-02-13 01:15 PM, Christian König wrote:
>>> Am 13.02.2018 um 18:18 schrieb Felix Kuehling:
>>>
>>>> I don't see how you can have separate TTM objects referring to the
>>>> same memory.
>>> Well that is trivial, we do this all the time with prime and I+A laptops.
>> As I understand it, you use DMABuf to export/import buffers on multiple
>> devices. I believe all devices share a single amdgpu_bo, which contains
>> the ttm_buffer_object.
> The dma-buf exporter and importer can be different drivers, so this is
> not possible.

Yes. In the general case this is handled by SG tables. However, GEM and
AMDGPU have some special cases for importing buffers from the same driver.

The discussion here is about sharing BOs between different AMDGPU
devices (with or without involving DMABufs). I'm not talking about
sharing BOs with different drivers.

Regards
  Felix

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