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

[Felix Kuehling]

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.sie...@amd.com>
---
  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);