This is a note to let you know that I've just added the patch titled
drm/amdgpu: mask the xgmi number of hops reported from psp to kfd
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drm-amdgpu-mask-the-xgmi-number-of-hops-reported-fro.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 164c442056a6ba9f07997c2874450984c27697ee
Author: Jonathan Kim <jonathan.kim@xxxxxxx>
Date: Wed Jan 27 15:24:59 2021 -0500
drm/amdgpu: mask the xgmi number of hops reported from psp to kfd
[ Upstream commit 4ac5617c4b7d0f0a8f879997f8ceaa14636d7554 ]
The psp supplies the link type in the upper 2 bits of the psp xgmi node
information num_hops field. With a new link type, Aldebaran has these
bits set to a non-zero value (1 = xGMI3) so the KFD topology will report
the incorrect IO link weights without proper masking.
The actual number of hops is located in the 3 least significant bits of
this field so mask if off accordingly before passing it to the KFD.
Signed-off-by: Jonathan Kim <jonathan.kim@xxxxxxx>
Reviewed-by: Amber Lin <amber.lin@xxxxxxx>
Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_xgmi.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_xgmi.c
index 65aae75f80fd..ce1048bad158 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_xgmi.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_xgmi.c
@@ -311,15 +311,22 @@ int amdgpu_xgmi_update_topology(struct amdgpu_hive_info *hive, struct amdgpu_dev
}
+/*
+ * NOTE psp_xgmi_node_info.num_hops layout is as follows:
+ * num_hops[7:6] = link type (0 = xGMI2, 1 = xGMI3, 2/3 = reserved)
+ * num_hops[5:3] = reserved
+ * num_hops[2:0] = number of hops
+ */
int amdgpu_xgmi_get_hops_count(struct amdgpu_device *adev,
struct amdgpu_device *peer_adev)
{
struct psp_xgmi_topology_info *top = &adev->psp.xgmi_context.top_info;
+ uint8_t num_hops_mask = 0x7;
int i;
for (i = 0 ; i < top->num_nodes; ++i)
if (top->nodes[i].node_id == peer_adev->gmc.xgmi.node_id)
- return top->nodes[i].num_hops;
+ return top->nodes[i].num_hops & num_hops_mask;
return -EINVAL;
}
