Re: [PATCH] drm/amdkfd: set coherent host access capability flag

[Felix Kuehling <felix.kuehling@xxxxxxx>]

Am 2023-06-15 um 18:54 schrieb Alex Sierra:
> This flag determines whether the host possesses coherent access to
> the memory of the device.
>
> Signed-off-by: Alex Sierra <alex.sierra@xxxxxxx>
> ---
>   drivers/gpu/drm/amd/amdkfd/kfd_topology.c | 4 ++++
>   1 file changed, 4 insertions(+)
>
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_topology.c b/drivers/gpu/drm/amd/amdkfd/kfd_topology.c
> index 90b86a6ac7bd..7ede3de4f7fb 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_topology.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_topology.c
> @@ -2107,6 +2107,10 @@ int kfd_topology_add_device(struct kfd_node *gpu)
>   	if (KFD_IS_SVM_API_SUPPORTED(dev->gpu->adev))
>   		dev->node_props.capability |= HSA_CAP_SVMAPI_SUPPORTED;
>   
> +	if (dev->gpu->adev->gmc.is_app_apu |
> +		dev->gpu->adev->gmc.xgmi.connected_to_cpu)
> +		dev->node_props.capability |= HSA_CAP_FLAGS_COHERENTHOSTACCESS;

I believe this is not true for "small APUs" because they map the 
framebuffer as WC on the CPU. I think you need to check specifically for 
APP APU.

Regards,
  Felix


> +
>   	kfd_debug_print_topology();
>   
>   	kfd_notify_gpu_change(gpu_id, 1);