Score:0

Switching to modesetting; Light Display Manager fails to start without Intel driver or xorg.conf.d

cn flag

Goal

I wish to use the modesetting graphics dr-ver instead of the intel graphics dr-ver.


Note

I was only able to get around the automated spam filter by replacing invocations of "driver" with "dr-ver". See this.


Impetus

My current graphics configuration results in two problems:

  • bizarre graphics flickering and artifacting when using three external monitors connected via a Thunderbolt 3 dock
  • the AMD GPU does not work (DRI_PRIME=1 glxgears yields only a black box)

Problem

LightDM fails to start if I perform any of the following:

  • apt remove xserver-xorg-video-intel-hwe-18.04 package
  • mv /usr/share/X11/xorg.conf.d /usr/share/X11/xorg.conf.d.backup (effectively removing the Xorg configuration; my understanding is that it is no longer necessary?)
  • change the Dr-ver entry in my 10-intel.conf OutputClass from "intel" to "modesetting"

LightDM complains:

Failed to start Detect the available GPUs and deal with any system changes

➜  ~ journalctl -u lightdm.service

... < repeated five times before final failure > ...

Sep 17 13:04:58 Precision-3540 systemd[1]: Starting Light Display Manager...
Sep 17 13:04:58 Precision-3540 systemd[1]: Started Light Display Manager.
Sep 17 13:04:58 Precision-3540 systemd[1]: lightdm.service: Main process exited, code=exited, status=1/FAILURE
Sep 17 13:04:58 Precision-3540 systemd[1]: lightdm.service: Failed with result 'exit-code'.
Sep 17 13:04:59 Precision-3540 systemd[1]: lightdm.service: Service hold-off time over, scheduling restart.
Sep 17 13:04:59 Precision-3540 systemd[1]: lightdm.service: Scheduled restart job, restart counter is at 5.
Sep 17 13:04:59 Precision-3540 systemd[1]: Stopped Light Display Manager.
Sep 17 13:04:59 Precision-3540 systemd[1]: lightdm.service: Start request repeated too quickly.
Sep 17 13:04:59 Precision-3540 systemd[1]: lightdm.service: Failed with result 'exit-code'.
Sep 17 13:04:59 Precision-3540 systemd[1]: Failed to start Light Display Manager.

➜  ~ journalctl -u gpu-manager.service
Sep 17 13:03:36 Precision-3540 systemd[1]: Starting Detect the available GPUs and deal with any system changes...
Sep 17 13:03:36 Precision-3540 systemd[1]: Started Detect the available GPUs and deal with any system changes.

... < repeated many times before logging a failure > ...

Sep 17 13:03:36 Precision-3540 systemd[1]: gpu-manager.service: Start request repeated too quickly.
Sep 17 13:03:36 Precision-3540 systemd[1]: gpu-manager.service: Failed with result 'start-limit-hit'.
Sep 17 13:03:36 Precision-3540 systemd[1]: Failed to start Detect the available GPUs and deal with any system changes.

Diagnostic Information

➜  ~ inxi --version 
inxi 3.3.06-00 (2021-07-21)
... < colophon and license elided > ... 

➜  ~ DRI_PRIME=0 inxi -Gxxxz
Graphics:  Device-1: Intel vendor: Dell dr-ver: i915 v: kernel bus-ID: 00:02.0 chip-ID: 8086:3ea0 class-ID: 0300 
           Device-2: Advanced Micro Devices [AMD/ATI] Lexa XT [Radeon PRO WX 3100] vendor: Dell dr-ver: amdgpu v: kernel 
           bus-ID: 3b:00.0 chip-ID: 1002:6985 class-ID: 0380 
           Device-3: Logitech Webcam C270 type: USB dr-ver: snd-usb-audio,uvcvideo bus-ID: 7-3:2 chip-ID: 046d:0825 
           class-ID: 0102 serial: <filter> 
           Display: x11 server: X.Org 1.20.8 compositor: gnome-shell v: 3.28.4 dr-ver: loaded: amdgpu,ati,intel 
           unloaded: fbdev,modesetting,vesa resolution: 1: 900x1600~60Hz 2: 900x1600~60Hz 3: 2560x1440~60Hz s-dpi: 96 
           OpenGL: renderer: Mesa DRI Intel UHD Graphics 620 (WHL GT2) v: 4.6 Mesa 20.0.8 compat-v: 3.0 direct render: Yes

➜  ~ DRI_PRIME=1 inxi -Gxxxz
Graphics:  Device-1: Intel vendor: Dell dr-ver: i915 v: kernel bus-ID: 00:02.0 chip-ID: 8086:3ea0 class-ID: 0300 
           Device-2: Advanced Micro Devices [AMD/ATI] Lexa XT [Radeon PRO WX 3100] vendor: Dell dr-ver: amdgpu v: kernel 
           bus-ID: 3b:00.0 chip-ID: 1002:6985 class-ID: 0380 
           Device-3: Logitech Webcam C270 type: USB dr-ver: snd-usb-audio,uvcvideo bus-ID: 7-3:2 chip-ID: 046d:0825 
           class-ID: 0102 serial: <filter> 
           Display: x11 server: X.Org 1.20.8 compositor: gnome-shell v: 3.28.4 dr-ver: loaded: amdgpu,ati,intel 
           unloaded: fbdev,modesetting,vesa resolution: 1: 900x1600~60Hz 2: 900x1600~60Hz 3: 2560x1440~60Hz s-dpi: 96 
           OpenGL: renderer: AMD Radeon Pro WX3100 (POLARIS12 DRM 3.35.0 5.4.0-84-generic LLVM 9.0.1) v: 4.5 Mesa 19.2.2 
           direct render: Yes

I think it is weird that I have the nouveau dr-ver as well, but that is the least of my concerns right now.

➜  ~ sudo apt list --installed | grep xserver-xorg-video
xserver-xorg-video-all-hwe-18.04/bionic-updates,now 1:7.7+19ubuntu8~18.04.3 amd64 [installed,automatic]
xserver-xorg-video-amdgpu-hwe-18.04/bionic-updates,now 19.1.0-1~18.04.1 amd64 [installed,automatic]
xserver-xorg-video-ati-hwe-18.04/bionic-updates,now 1:19.1.0-1~18.04.1 amd64 [installed,automatic]
xserver-xorg-video-fbdev-hwe-18.04/bionic-updates,now 1:0.5.0-1ubuntu1~18.04.1 amd64 [installed,automatic]
xserver-xorg-video-intel-hwe-18.04/bionic-updates,now 2:2.99.917+git20171229-1ubuntu1~18.04.1 amd64 [installed]
xserver-xorg-video-nouveau-hwe-18.04/bionic-updates,now 1:1.0.16-1~18.04.1 amd64 [installed,automatic]
xserver-xorg-video-qxl-hwe-18.04/bionic-updates,now 0.1.5-2build2~18.04.1 amd64 [installed,automatic]
xserver-xorg-video-radeon-hwe-18.04/bionic-updates,now 1:19.1.0-1~18.04.1 amd64 [installed,automatic]
xserver-xorg-video-vesa-hwe-18.04/bionic-updates,now 1:2.4.0-1~18.04.1 amd64 [installed,automatic]
xserver-xorg-video-vmware-hwe-18.04/bionic-updates,now 1:13.3.0-2build1~18.04.1 amd64 [installed,automatic]

Xorg Information

The contents of /var/log/Xorg.0.log are too long to post in full. However, I can include a few highlights:

[     6.350] (==) Using system config directory "/usr/share/X11/xorg.conf.d"
...
[     6.377] (II) Applying OutputClass "Intel" to /dev/dri/card0
[     6.377]    loading dr-ver: intel
[     6.377] (II) Applying OutputClass "AMDgpu" to /dev/dri/card1
[     6.377]    loading dr-ver: amdgpu
[     6.377] (==) Matched intel as autoconfigured dr-ver 0
[     6.377] (==) Matched amdgpu as autoconfigured dr-ver 1
[     6.377] (==) Matched ati as autoconfigured dr-ver 2
[     6.377] (==) Matched modesetting as autoconfigured dr-ver 3
[     6.377] (==) Matched fbdev as autoconfigured dr-ver 4
[     6.377] (==) Matched vesa as autoconfigured dr-ver 5
[     6.377] (==) Assigned the dr-ver to the xf86ConfigLayout
[     6.377] (II) LoadModule: "intel"
[     6.377] (II) Loading /usr/lib/xorg/modules/dr-vers/intel_drv.so
[     6.379] (II) Module intel: vendor="X.Org Foundation"
[     6.379]    compiled for 1.20.1, module version = 2.99.917
[     6.379]    Module class: X.Org Video Dr-ver
[     6.379]    ABI class: X.Org Video Dr-ver, version 24.0
[     6.379] (II) LoadModule: "amdgpu"
[     6.379] (II) Loading /usr/lib/xorg/modules/dr-vers/amdgpu_drv.so
[     6.383] (II) Module amdgpu: vendor="X.Org Foundation"
[     6.383]    compiled for 1.20.5, module version = 19.1.0
[     6.383]    Module class: X.Org Video Dr-ver
[     6.383]    ABI class: X.Org Video Dr-ver, version 24.0
... < also loads ati, fbdev, vesa > ...
[     6.395] (II) LoadModule: "modesetting"
[     6.395] (II) Loading /usr/lib/xorg/modules/dr-vers/modesetting_drv.so
[     6.397] (II) Module modesetting: vendor="X.Org Foundation"
[     6.397]    compiled for 1.20.8, module version = 1.20.8
[     6.397]    Module class: X.Org Video Dr-ver
[     6.397]    ABI class: X.Org Video Dr-ver, version 24.1
...
[     6.420] (II) AMDGPU(G0): [KMS] Kernel modesetting enabled.
...
[     6.651] (II) UnloadModule: "modesetting"
[     6.651] (II) Unloading modesetting
➜  xorg.conf.d cat 10-amdgpu.conf && cat 10-intel.conf 
Section "OutputClass"
    Identifier "AMDgpu"
    MatchDr-ver "amdgpu"
    Dr-ver "amdgpu"
EndSection

Section "OutputClass"
   Identifier "Intel"
   MatchDr-ver "i915"
   Dr-ver "intel"
EndSection

Booting from Ubuntu 20.04 or Kubuntu 21.04 live media leads to a flawless experience. Unfortunately upgrading or reinstalling is not an option at this time. I have to fix the configuration manually somehow.

Thanks in advance!

mangohost

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