[PATCH 2/2] drm/amdgpu: Let KFD use more VMIDs on Arcturus

[Felix Kuehling]

Am 2020-06-25 um 4:19 a.m. schrieb Christian König:
> Am 25.06.20 um 05:18 schrieb Felix Kuehling:
>> When there is no graphics support, KFD can use more of the VMIDs.
>> Graphics
>> VMIDs are only used for video decoding/encoding and post processing.
>> With
>> two VCE engines, there is no reason to reserve more than 2 VMIDs for
>> that.
>
> IIRC the expectation is that we still use the compute queues for post
> processing and not the KFD.
>
> So we will need at least VMIDs for that as well.

Correct. Post processing uses compute queues and VMIDs in the GFXHUB.
VCE uses VMIDs in the MMHUB. I believe in Mesa they use the same VM
context. So can't they share the same VMIDs?

Regards,
  Felix


>
>>
>> Signed-off-by: Felix Kuehling <Felix.Kuehling at amd.com>
>> ---
>>   drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c | 11 ++++++++---
>>   1 file changed, 8 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
>> b/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
>> index 6e10b42c57e5..3470929e5b8e 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
>> @@ -1245,10 +1245,15 @@ static int gmc_v9_0_sw_init(void *handle)
>>       /*
>>        * number of VMs
>>        * VMID 0 is reserved for System
>> -     * amdgpu graphics/compute will use VMIDs 1-7
>> -     * amdkfd will use VMIDs 8-15
>> +     * amdgpu graphics/compute will use VMIDs 1..n-1
>> +     * amdkfd will use VMIDs n..15
>> +     *
>> +     * The first KFD VMID is 8 for GPUs with graphics, 3 for
>> +     * compute-only GPUs. On compute-only GPUs that leaves 2 VMIDs
>> +     * for video processing.
>>        */
>> -    adev->vm_manager.first_kfd_vmid = 8;
>> +    adev->vm_manager.first_kfd_vmid =
>> +        adev->asic_type == CHIP_ARCTURUS ? 3 : 8;
>>         amdgpu_vm_manager_init(adev);
>>   
>