[PATCH] drm/amdgpu: refine kiq read register

[Felix Kuehling]

Am 2020-04-20 um 3:42 a.m. schrieb Tao, Yintian:
> Hi  Felix
>
> I have one question about function kgd_gfx_v9_hiq_mqd_load(). I see it directly write contents into kiq ring and not wait for the fence. Do you know how KFD know the hiq_mqd_load complete? Thanks in advance.

That's probably a bug. I think we can get away with it, because the HIQ
is only used once the first user mode
KFD process is started.

Worst case, KFD will submit something to the HIQ before it's mapped, and
the doorbell update will be missed. So KFD will think the HIQ is hanging
and trigger a GPU reset.

Regards,
  Felix


>
>
>
> Best Regards
> Yintian Tao