Getting a new AMD GPU to work on Ubuntu 18.04

Posted
By haxj
5 min read

amd-chip Image by u/RenderBender_Uranus

Summary

Today I got to install Ubuntu 18.04 on a brand new laptop, which features a 2020 AMD Renoir inside. The OS and GPU doesn’t like to work with each other, so I have to find some way to fix that.

TL;DR

To get newer AMD GPU (AMD Renoir, in this particular case) to work on Ubuntu 18.04:

  • Use a newer kernel version (I tested with 5.8, other versions may also work)
  • Enable early KMS start for amdgpu

Full story

Problems

Why not just use Ubuntu 20.04, you might ask, but that’s a story for another day. After installing Ubuntu Server 18.04 and i3 without major problems, I notice some strange problems with the display. This is when I start to go down the rabbit hole of GPU drivers on Linux.

Some problems I encountered:

  • brightnessctl doesn’t work. No errors but doesn’t change brightness.
  • compton compositor with glx backend freezes the session.

Diagnose the problems

Ok, the problems suggest something’s wrong with the graphical system. Let’s check the system:

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$ lspci -nn | grep -E -- 'VGA|Display'
03:00.0 VGA compatible controller [0300]: Advanced Micro Devices, Inc. [AMD/ATI] Device [1002:1636] (rev d1)

We have an AMD GPU here. The device ID is 1636.

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$ xrandr --listproviders
Providers: number : 0

Oops. On a normal system, number should be 1 or more.

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$ glxinfo | grep OpenGL
OpenGL vendor string: VMware, Inc.
OpenGL renderer string: llvmpipe (LLVM 10.0.0, 128 bits)
...

OpenGL vendor string here is VMware (strange, right?), and OpenGL renderer string is llvmpipe. llvmpipe is a software renderer, meaning GPU is not being used to rendering.

Let check if driver for the GPU is loaded.

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$ lspci -nnk -d 1002:1636 | grep Kernel
<nothing>

So no driver is loaded to control this GPU. As this AMD chip is released in 2020, the driver should be amdgpu. Let’s check if amdgpu support this device.

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$ modinfo amdgpu | grep 1636  # 1636 is device ID
<nothing>

So amdgpu does not support this GPU. Wait, what kernel are we using?

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$ uname -r
4.15.0-147-generic

That sounds pretty old! Indeed, a quick search on Wikipedia shows that it has reached EOL since 2018. It’s likely that this kernel does not support a 2020 GPU. We need a newer kernel.

Basically, I encountered this bug: FBDEV in use with amdgpu and there is no /dev/dri/card0 (hardware is AMD/ATI Renoir [1002:1636]). Although the bug is marked as Fix Released, it does not provide any workaround for Ubuntu 18.04. So I have to find my own.

Solutions, part 1: Install newer kernel and firmware

To install a newer Linux kernel on Ubuntu, we have 3 main choices, in order of increasing difficulty:

  • Install the Ubuntu HWE kernel
  • Install a kernel from Ubuntu Mainline Kernel PPA
  • Build and install your own kernel manually

(1) is easiest, but doesn’t work. Maybe the kernel isn’t new enough (As of 06/2021, HWE kernel of Ubuntu 18.04 is 5.4).

Let’s install kernel 5.8 with (2). Go to https://kernel.ubuntu.com/~kernel-ppa/mainline/v5.8.18/amd64/. We see the following files:

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linux-headers-5.8.18-050818-generic_5.8.18-050818.202011011237_amd64.deb
linux-headers-5.8.18-050818-lowlatency_5.8.18-050818.202011011237_amd64.deb
linux-headers-5.8.18-050818_5.8.18-050818.202011011237_all.deb
linux-image-unsigned-5.8.18-050818-generic_5.8.18-050818.202011011237_amd64.deb
linux-image-unsigned-5.8.18-050818-lowlatency_5.8.18-050818.202011011237_amd64.deb
linux-modules-5.8.18-050818-generic_5.8.18-050818.202011011237_amd64.deb
linux-modules-5.8.18-050818-lowlatency_5.8.18-050818.202011011237_amd64.deb

We don’t need the 3 deb files with “lowlatency” in the file name. Downloads the other 4 deb files to a new folder (linux-v5.8.18), then install all of them:

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$ cd <path>/linux-v5.8.18
$ sudo dpkg -i *.deb
<some output>

To support newer GPUs, we also need the new firmwares.

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$ git clone https://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git
<some output>
$ cd linux-firmware
$ cp -r /lib/firmware/amdgpu/ ~/backup_amdgpu  # Backup original firmwares
$ sudo cp amdgpu/* /lib/firmware/amdgpu/

At this point, you may think things should work now. However, if we reboot now, we will stuck at the following error:

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fb0: switching to amdgpudrmfb from efi vga

If you don’t care about debugging the problems, don’t reboot and skip to the solution section.

Diagnose again

To diagnose the problem, we need to boot to the newer kernel. A quick search suggests we have to pass the option nomodeset to kernel at boot.

After booting into the graphical system, the problem still persist. Let’s check if this version of amdgpu support our GPU:

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$ modinfo amdgpu | grep 1636
alias:          pci:v00001002d00001636sv*sd*bc*sc*i*

Yes, the amdgpu driver does indeed support our GPU. So why doesn’t it work?

A very long Googling process lead me to check the xorg log file:

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$ less /var/log/Xorg.0.log
...
[   4.988] (II) VESA: driver for VESA chipsets: vesa
[   4.988] (EE) open /dev/dri/card0: No such file or directory
[   4.988] (WW) Falling back to old probe method for modesetting
[   4.988] (EE) open /dev/dri/card0: No such file or directory
[   4.988] (II) Loading sub module "fbdevhw"
[   4.988] (II) LoadModule: "fbdevhw"
...

So, more errors…

Solutions, part 2: Enable early KMS for amdgpu

After a very long searching and trying many things without success, I found this post in which someone suggests enabling early KMS start for amdgpu. I’m not even sure but tried anyway and surprisingly, it works!

First, lets add amdgpu to /etc/initramfs-tools/modules. Then update initramfs:

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$ sudo update-initramfs -u
<some output>

Then reboot. Let’s check again:

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$ glxinfo | grep OpenGL
OpenGL vendor string: X.Org
OpenGL renderer string: AMD RENOIR (DRM 3.38.0, 5.8.18-050818-generic, LLVM 10.0.0)
...

And voila! Now OpenGL renderer is not llvmpipe but AMD RENOIR, meaning the GPU is being used for rendering. Let’s check xrandr:

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$ xrandr --listproviders
Providers: number : 1
Provider 0: id: 0x57 cap: 0x9, Source Output, Sink Offload crtcs: 4 outputs: 4 associated providers: 0 name:Unknown AMD Radeon GPU @ pci:0000:03:00.0

So all good. Now we can use brightnessctl and compton without problems.

Update on 2021/07/04:

There are many details about Linux graphics system that I do not understand very well. I find another detailed article which address similar problem with Ubuntu 16.04: Using the newer AMDGPU driver on Ubuntu 16.04LTS

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linux kernel gpu amd bugs ubuntu
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