Re: [PATCH 1/2] drm/amdgpu/gmc: add a way to force a particular placement for GART

["Christian König" <ckoenig.leichtzumerken@gmail.com>]

I'm still not happy with moving the GART fixed to the end. We abandoned 
this for good reasons.

If we really go this way I would prefer to have this as parameter to the 
amdgpu_gmc_gart_location() function and not in the gmc structure.

Regards,
Christian.

Am 26.09.23 um 19:30 schrieb Alex Deucher:
> Ping on this series?
>
> On Thu, Sep 21, 2023 at 5:46 PM Alex Deucher <alexander.deucher@amd.com> wrote:
>> We normally place GART based on the location of VRAM and the
>> available address space around that, but provide an option
>> to force a particular location for hardware that needs it.
>>
>> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
>> ---
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c | 19 +++++++++++++++----
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.h |  8 ++++++++
>>   2 files changed, 23 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c
>> index f74a51a93ebb..d1d98488373b 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c
>> @@ -287,11 +287,22 @@ void amdgpu_gmc_gart_location(struct amdgpu_device *adev, struct amdgpu_gmc *mc)
>>                  mc->gart_size = max(size_bf, size_af);
>>          }
>>
>> -       if ((size_bf >= mc->gart_size && size_bf < size_af) ||
>> -           (size_af < mc->gart_size))
>> -               mc->gart_start = 0;
>> -       else
>> +       switch (mc->gart_placement) {
>> +       case AMDGPU_GART_PLACEMENT_HIGH:
>>                  mc->gart_start = max_mc_address - mc->gart_size + 1;
>> +               break;
>> +       case AMDGPU_GART_PLACEMENT_LOW:
>> +               mc->gart_start = 0;
>> +               break;
>> +       case AMDGPU_GART_PLACEMENT_BEST_FIT:
>> +       default:
>> +               if ((size_bf >= mc->gart_size && size_bf < size_af) ||
>> +                   (size_af < mc->gart_size))
>> +                       mc->gart_start = 0;
>> +               else
>> +                       mc->gart_start = max_mc_address - mc->gart_size + 1;
>> +               break;
>> +       }
>>
>>          mc->gart_start &= ~(four_gb - 1);
>>          mc->gart_end = mc->gart_start + mc->gart_size - 1;
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.h
>> index dd0ede75e5d7..fcef057b9213 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.h
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.h
>> @@ -199,6 +199,12 @@ struct amdgpu_mem_partition_info {
>>
>>   #define INVALID_PFN    -1
>>
>> +enum amdgpu_gart_placement {
>> +       AMDGPU_GART_PLACEMENT_BEST_FIT = 0,
>> +       AMDGPU_GART_PLACEMENT_HIGH,
>> +       AMDGPU_GART_PLACEMENT_LOW,
>> +};
>> +
>>   struct amdgpu_gmc {
>>          /* FB's physical address in MMIO space (for CPU to
>>           * map FB). This is different compared to the agp/
>> @@ -339,6 +345,8 @@ struct amdgpu_gmc {
>>          bool flush_tlb_needs_extra_type_0;
>>          bool flush_tlb_needs_extra_type_2;
>>          bool flush_pasid_uses_kiq;
>> +
>> +       enum amdgpu_gart_placement gart_placement;
>>   };
>>
>>   #define amdgpu_gmc_emit_flush_gpu_tlb(r, vmid, addr) (r)->adev->gmc.gmc_funcs->emit_flush_gpu_tlb((r), (vmid), (addr))
>> --
>> 2.41.0
>>