WARNING: CPU: 11 PID: 1137 at drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm_mst_types.c:88 dm_dp_aux_transfer+0xa5/0xc0 [amdgpu]

Submitted by Marc Thomas

Assigned to Default DRI bug account

Link to original bug (#107456)

Description

Created attachment 140936
dmesg output

I see the following warning during boot with Linux kernel 4.18.0-rc6 & 4.17.10:

root@deepthought:~# dmesg | grep WARN
[ 9.346100] WARNING: CPU: 11 PID: 1137 at drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm_mst_types.c:88 dm_dp_aux_transfer+0xa5/0xc0 [amdgpu]
[ 9.346162] WARNING: CPU: 14 PID: 1139 at drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm_mst_types.c:88 dm_dp_aux_transfer+0xa5/0xc0 [amdgpu]


Hardware is Ryzen 7 2700x, Sapphire Technology Radeon RX 480, IIyama ProLite XB2380HS connected via DVI.

It looks like "dm_dp_aux_transfer" is used to setup DisplayPort, using "struct drm_dp_aux_msg — DisplayPort AUX channel transaction". Now, with my hardware I don't have any monitors connected via DisplayPort. Is that relevant?

I patched in a "printk("msg->size = %d\n", msg->size);" and it displays the result twice, which is curious.

dmesg | grep -i "msg->size"

[ 9.469511] msg->size = -5
[ 9.469803] msg->size = -5

Anyway, full "dmesg" attached.

Attachment 140936, "dmesg output":
dmesg.4.18.0-rc6_MST