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Epoxyc

Member

From: Tokyo

Registered: 2016-03-01

Posts: 33

Radeon Vega eGPU on a laptop with optimus hardware

Hi!
I got a Radeon Vega 56 in an external case from a friend and I am trying to use it with my laptop, An Asus UX501VW which has an integrated chip (HD Graphics 530 from a i7­-6700HQ) and also Nvidia 960m.
I am using the NVIDIA Graphics only setup from the wiki and everything works flawlessly (on X, it is not possible to use wayland with this setup).

I tried to plug the eGPU to the USB-C port of my laptop with a monitor plugged on it and, to my surprise, it worked! But I had many artifacts (thinking about it now, I am not sure that the AMD card was actually doing the rendering).
So I am trying to make a very simple setup using only the AMD card on the external monitor only for now. I removed the previous X configuration, installed xf86-video-amdgpu put amdgpu instead of nvidia in my initramfs for early KMS.

However when I start Gnome on Wayland, only the Intel card is used and when I try with X, it crashes back to GDM.

$lspci | grep AMD
09:00.0 PCI bridge: Advanced Micro Devices, Inc. [AMD] Vega 10 PCIe Bridge (rev c3)
0a:00.0 PCI bridge: Advanced Micro Devices, Inc. [AMD] Vega 10 PCIe Bridge
0b:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Vega 10 XL/XT [Radeon RX Vega 56/64] (rev c3)
0b:00.1 Audio device: Advanced Micro Devices, Inc. [AMD/ATI] Vega 10 HDMI Audio [Radeon Vega 56/64]

But apparently the device is not detected by the driver:

[    28.616] (II) LoadModule: "amdgpu"
[    28.616] (II) Loading /usr/lib/xorg/modules/drivers/amdgpu_drv.so
[    28.620] (II) Module amdgpu: vendor="X.Org Foundation"
[    28.620]    compiled for 1.20.8, module version = 19.1.0
[    28.620]    Module class: X.Org Video Driver
[    28.620]    ABI class: X.Org Video Driver, version 24.1
[    28.620] (II) AMDGPU: Driver for AMD Radeon:
        All GPUs supported by the amdgpu kernel driver
[    28.620] (EE) No devices detected.
[    28.620] (EE) 
Fatal server error:
[    28.620] (EE) no screens found(EE) 
[    28.620] (EE) 
Please consult the The X.Org Foundation support 
         at http://wiki.x.org
 for help. 

Any idea on how I could get it work?

Thank you in advance!

Lone_Wolf

Member

From: Netherlands, Europe

Registered: 2005-10-04

Posts: 11,911

Re: Radeon Vega eGPU on a laptop with optimus hardware

Not going go be easy, https://jdloft.com/egpus-on-linux/ seems relevant

---

Disliking systemd intensely, but not satisfied with alternatives so focusing on taming systemd.

(A works at time B)  && (time C > time B ) ≠  (A works at time C)

Epoxyc

Member

From: Tokyo

Registered: 2016-03-01

Posts: 33

Re: Radeon Vega eGPU on a laptop with optimus hardware

Thank you very much for the link!
I'll give a try to solution (2), since I am already stuck with X11 because of the NVIDIA and I only use this laptop as a desktop one now.

EDIT:
Apparently the systemd service runs before the GPU is detectable on the thunderbolt interface, so it does not work automatically.
But I don't mind running "egpu-switcher switch internal/external" when I need to unplug the external GPU.

Thank you very much again! I'll now try to get Freesync/HDR working and reduce this hairdryer noise.

Last edited by Epoxyc (2020-10-10 06:23:02)