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I'm on Ubuntu 20.04 and it was working fine but after a recent reboot before which I had run some updates I can no longer log in as it never gets to the GUI login screen.

If I do Alt ctrl F2, I can login there but if I run something like startx that errors out and xrandr can't find any displays.

So I'm guessing this is a kernel issue? Any help/guidance would be appreciated.

Apologies for typos I'm writing from a phone

Tejas Lotlikar
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evan54
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    Same here. Able to boot only in recovery mode or using Alt+F* and startx but I don't have proper display drivers (there is warning that system works without hardware acceleration) and wifi. Spent few hours yesterday without success. Changed splash silent to nosplash debug in GRUB config so I can see that system stuck on "Reached target Host and Network Name Lookups". I also had to disable SSSD and re-install sddm-theme-breeze because it was somehow removed and login screen was broken. I've upgraded to 20.10 and forced 5.8.0 kernel but it didn't help. – Wirone Dec 02 '20 at 12:07
  • Today small update popped up and https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1903397 was mentioned in the description of kernel-related package, but it didn't help too. I've enabled proposed updates and updated everything, still without success. I have to work on recovery mode since booting using startx is barely usable (very slow animations, like Power Point slides). – Wirone Dec 02 '20 at 12:10
  • I uninstalled amdgpu by running amdgpu-pro-uninstall and this got me back seems has worked for others here as well https://askubuntu.com/questions/799515/black-screen-on-boot-after-amdgpu-pro-install-16-04. But I still don't have the graphics card properly loaded as I can't extend to a 2nd monitor for example – evan54 Dec 02 '20 at 12:56

3 Answers3

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Success!

I was able to boot normally, with fully working system. What I did was installing mainline tool (method #3 from here → https://linuxhint.com/update_ubuntu_kernel_20_04/):

sudo apt-add-repository -y ppa:cappelikan/ppa
sudo apt update
sudo apt install mainline

(I had to edit sources list and change from groovy to focal)

Then I installed 5.9.12 kernel using Mainline installer and after rebooting everything worked fine (I saw that even earlier because my external monitor started to work while booting).

Additionally I've removed wireguard package because there was warnings while building GRUB images and since I don't use WG anymore I just uninstalled it. But I believe actual fix was delivered in 5.9 kernel.

Wirone
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  • interesting do you know what linux kernel you were on before? I'm at 5.4.0.56 when I run uname -r – evan54 Dec 02 '20 at 13:20
  • I had 5.4.0-56, 5.8.0-29 (both signed) and 5.8.0-31 (unsigned), each of them had the same issue. – Wirone Dec 02 '20 at 13:23
  • And were you on an amd processor, did you have to install amdgpu? – evan54 Dec 02 '20 at 13:25
  • I didn't touch amdgpu in any way, before the crash and after that. I just tested many kernels and 5.9.12 actually worked :-) – Wirone Dec 02 '20 at 13:31
  • FYI:

    -> % dpkg --list | egrep -i 'amdgpu'
    ii libdrm-amdgpu1:amd64 2.4.102-1ubuntu1 amd64 Userspace interface to amdgpu-specific kernel DRM services -- runtime ii xserver-xorg-video-amdgpu 19.1.0-2 amd64 X.Org X server -- AMDGPU display driver

     – Wirone Dec 02 '20 at 13:32
  • do you know if what you have done will allow ubuntu to update to kernels in the futrue? or have you overridden that part by manually selecting a kernel? – evan54 Dec 02 '20 at 16:45
  • @evan54 Honestly I don't know how it will act in the future, for now I don't think about it since I needed working system for my work :-) I think (and hope) that if kernel delivered in 21.04 will be newer than installed with mainline it will be updgraded. Otherwise, I'll install it manually. – Wirone Dec 03 '20 at 16:22
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I thought I'd add because I tried all these possible answers and it didn't work.

I have an old Nvidia GPU (GeForce 9600 GT) and I had to reinstall the display manager, reinstall the desktop environment and then reinstall the graphics driver. It seems that an update made the normal driver fail (nvidia-340) and I needed a different driver.

sudo apt install xserver-xorg-video-nouveau
Greenonline
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backuey
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I played around with several kernels and mainland didn't work for me.

Mainland problem:

  • Kernels weren't signed

Installing kernels manually:

  • tried installing 5.4.0.52 and 5.4.0.53 by doing the equivalent below:

sudo apt install linux-image-5.4.0-53-generic linux-headers-5.4.0-53-generic

That didn't work either - the mouse and wifi also didn't work.

What ultimately worked for me was:

sudo apt install linux-generic-hwe-20.04-edge

evan54
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  • I have secure boot disabled in BIOS so I could use unsigned kernel. But yeah, if you need secure boot, my answer does not fix the problem. – Wirone Dec 03 '20 at 16:23