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catniptwinz

Member

Registered: 2020-11-09

Posts: 10

[SOLVED] xorg fails to start with kernel 5.12.8

After upgrading from kernel 5.12.7 to 5.12.8, xorg fails to start:

[    40.848] (EE) open /dev/dri/card0: No such file or directory
[    40.848] (WW) Falling back to old probe method for modesetting
[    40.848] (EE) open /dev/dri/card0: No such file or directory
[    40.848] vesa: Refusing to run on UEFI
[    40.848] (WW) VGA arbiter: cannot open kernel arbiter, no multi-card support
[    40.848] (EE) Screen 0 deleted because of no matching config section.
[    40.848] (II) UnloadModule: "modesetting"
[    40.848] (EE) Device(s) detected, but none match those in the config file.
[    40.848] (EE) 
Fatal server error:
[    40.848] (EE) no screens found(EE) 

The system is a thinkpad t495 with radeon vega 8 graphics, i.e. amdgpu. I'm booting with EFISTUB and calling 'exec startx' from ~/.bash_profile

Loading amdgpu with early KMS does not fix the issue. Downgrading the kernel to 5.12.7 works, but I'm considering this a temporary fix and would appreciate some help understanding how I might find the source of this problem and what I can do about it.

Using 5.12.7, xorg logs show:

[    42.674] (II) xfree86: Adding drm device (/dev/dri/card0)
[    42.674] (II) systemd-logind: got fd for /dev/dri/card0 226:0 fd 10 paused 0

but these lines are not present with 5.12.8.

With 5.12.7:

ls /dev/dri

by-path  card0  renderD128

With 5.12.8:

ls: cannot access '/dev/dri': No such file or directory

With 5.12.8,

pacman -Qi linux

shows 5.12.8 but

uname -a

shows 5.12.7 (yes, this is after reboot).

I've confirmed that /boot was mounted during kernel installation and all mtimes of files under /boot reflect that they were updated during installation.

For comparison, kernel 5.12.8 works as expected on a thinkpad t420 with intel graphics (i915 loaded via early KMS), also booted with EFISTUB.

Here are full xorg logs and dmesg output with kernel 5.12.7 and 5.12.8:
Xorg.0.log 5.12.7
Xorg.0.log 5.12.8
dmesg 5.12.7
dmesg 5.12.8

Last edited by catniptwinz (2021-05-30 21:11:21)

seth

Member

From: Won't reply 2 private help req

Registered: 2012-09-03

Posts: 75,998

Re: [SOLVED] xorg fails to start with kernel 5.12.8

The amdgpu kernel module isn't loaded, the problem is very most likely

With 5.12.8,

pacman -Qi linux
shows 5.12.8 but

uname -a
shows 5.12.7 (yes, this is after reboot).

You're booting the old kernel and the installed modules don't match.
The reason is that either you forgot to mount the /boot partition during the update or that you're actually booting from the root partition.

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catniptwinz

Member

Registered: 2020-11-09

Posts: 10

Re: [SOLVED] xorg fails to start with kernel 5.12.8

The reason is that either you forgot to mount the /boot partition during the update or that you're actually booting from the root partition.

Indeed it was both, due to errors in /etc/fstab -- thanks. Marked solved.