drm/amdgpu: Inform if PCIe based P2P links are not available

Raise an info message in kernel log if PCIe root complex
determines that a AMD GPU device D<i> cannot have P2P
communication with another AMD GPU device D<j>

Signed-off-by: Ramesh Errabolu <Ramesh.Errabolu@amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index 38a1757..a72c90d 100644 (file)
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -6200,6 +6200,9 @@ bool amdgpu_device_is_peer_accessible(struct amdgpu_device *adev,
        bool p2p_access =
                !adev->gmc.xgmi.connected_to_cpu &&
                !(pci_p2pdma_distance(adev->pdev, peer_adev->dev, false) < 0);
+       if (!p2p_access)
+               dev_info(adev->dev, "PCIe P2P access from peer device %s is not supported by the chipset\n",
+                       pci_name(peer_adev->pdev));
 
        bool is_large_bar = adev->gmc.visible_vram_size &&
                adev->gmc.real_vram_size == adev->gmc.visible_vram_size;