Configuration for eGPU removed on update

[Alan Pope 🍺🐧🐱 🦄]

ThinkPad X1C9 running Kubuntu.
I'm using an external nVidia GPU in an enclosure, attached via thunderbolt.

I have applied updates over the last few weeks, and rebooted today.
Got a black screen. Turns out an update back in mid June (22nd) removed the Option
"AllowExternalGpus" "true" from my xorg.conf.

Why is an update removing a vital configuration option enabling me to display my login screen?

I had to re-edit the xorg.conf like an cave man from 20 years ago.

ProblemType: Bug
DistroRelease: Ubuntu 21.04
Package: xorg 1:7.7+22ubuntu1
ProcVersionSignature: Ubuntu 5.11.0-25.27-generic 5.11.22
Uname: Linux 5.11.0-25-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair nvidia_modeset nvidia
.proc.driver.nvidia.capabilities.gpu0: Error: path was not a regular file.
.proc.driver.nvidia.capabilities.mig: Error: path was not a regular file.
.proc.driver.nvidia.gpus.0000.52.00.0: Error: path was not a regular file.
.proc.driver.nvidia.registry: Binary: ""
.proc.driver.nvidia.suspend: suspend hibernate resume
.proc.driver.nvidia.suspend_depth: default modeset uvm
.proc.driver.nvidia.version:
 NVRM version: NVIDIA UNIX x86_64 Kernel Module 460.91.03 Fri Jul 2 06:04:10 UTC 2021
 GCC version:
ApportVersion: 2.20.11-0ubuntu65.1
Architecture: amd64
BootLog: Error: [Errno 13] Permission denied: '/var/log/boot.log'
CasperMD5CheckResult: pass
CompositorRunning: None
CurrentDesktop: KDE
Date: Tue Jul 27 16:42:11 2021
DistUpgraded: Fresh install
DistroCodename: hirsute
DistroVariant: ubuntu
DkmsStatus:
 tp_smapi, 0.43, 5.11.0-22-generic, x86_64: installed
 tp_smapi, 0.43, 5.11.0-25-generic, x86_64: installed
ExtraDebuggingInterest: Yes
GraphicsCard:
 Intel Corporation TigerLake GT2 [Iris Xe Graphics] [8086:9a49] (rev 01) (prog-if 00 [VGA controller])
   Subsystem: Lenovo Iris Xe Graphics [17aa:22d5]
 NVIDIA Corporation GP107 [GeForce GTX 1050 Ti] [10de:1c82] (rev a1) (prog-if 00 [VGA controller])
   Subsystem: ASUSTeK Computer Inc. GP107 [GeForce GTX 1050 Ti] [1043:85d1]
InstallationDate: Installed on 2021-05-14 (73 days ago)
InstallationMedia: Kubuntu 21.04 "Hirsute Hippo" - Release amd64 (20210420)
MachineType: LENOVO 20XWCTO1WW
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-5.11.0-25-generic root=UUID=f73d534c-9211-43d9-a8d5-fe9b6bffffb3 ro quiet splash vt.handoff=7
SourcePackage: xorg
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 03/26/2021
dmi.bios.release: 1.23
dmi.bios.vendor: LENOVO
dmi.bios.version: N32ET47W (1.23 )
dmi.board.asset.tag: Not Available
dmi.board.name: 20XWCTO1WW
dmi.board.vendor: LENOVO
dmi.board.version: SDK0J40697 WIN
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: None
dmi.ec.firmware.release: 1.22
dmi.modalias: dmi:bvnLENOVO:bvrN32ET47W(1.23):bd03/26/2021:br1.23:efr1.22:svnLENOVO:pn20XWCTO1WW:pvrThinkPadX1CarbonGen9:rvnLENOVO:rn20XWCTO1WW:rvrSDK0J40697WIN:cvnLENOVO:ct10:cvrNone:
dmi.product.family: ThinkPad X1 Carbon Gen 9
dmi.product.name: 20XWCTO1WW
dmi.product.sku: LENOVO_MT_20XW_BU_Think_FM_ThinkPad X1 Carbon Gen 9
dmi.product.version: ThinkPad X1 Carbon Gen 9
dmi.sys.vendor: LENOVO
version.compiz: compiz N/A
version.libdrm2: libdrm2 2.4.105-3~21.04.1
version.libgl1-mesa-dri: libgl1-mesa-dri 21.0.1-2
version.libgl1-mesa-glx: libgl1-mesa-glx N/A
version.nvidia-graphics-drivers: nvidia-graphics-drivers-* N/A
version.xserver-xorg-core: xserver-xorg-core 2:1.20.11-1ubuntu1.1
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev N/A
version.xserver-xorg-video-ati: xserver-xorg-video-ati N/A
version.xserver-xorg-video-intel: xserver-xorg-video-intel N/A
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau N/A

[Daniel van Vugt (vanvugt)]

Judging by the top of the config file it sounds like the Nvidia driver writing and overwriting it. There was an update to nvidia-graphics-drivers-460 on 21 July.

In theory this is what /usr/share/X11/xorg.conf.d/ is for, to add custom configs that other packages won't touch. But I don't know if spreading the nvidia config across multiple files with potentially duplicate sections would work.