Black screen after login when using CKLau-64HUA KVM switch

[Stapel]

After I log in from the login screen, I just get a black screen. To get a GUI, I then press "CTL+Alt+F4", to get a console login, and then do "sudo startx". I have tried both options from the bottom right corner for logging in.

ProblemType: Bug
DistroRelease: Ubuntu 22.04
Package: xorg 1:7.7+23ubuntu2
ProcVersionSignature: Ubuntu 5.15.0-27.28-generic 5.15.30
Uname: Linux 5.15.0-27-generic x86_64
NonfreeKernelModules: wl
ApportVersion: 2.20.11-0ubuntu82
Architecture: amd64
BootLog:

CasperMD5CheckResult: unknown
CompositorRunning: None
Date: Mon May 2 14:01:43 2022
DistroCodename: jammy
DistroVariant: ubuntu
DkmsStatus:
 bcmwl/6.30.223.271+bdcom, 5.13.0-22-generic, x86_64: installed
 bcmwl/6.30.223.271+bdcom, 5.13.0-40-generic, x86_64: installed
 bcmwl/6.30.223.271+bdcom, 5.15.0-27-generic, x86_64: installed
ExtraDebuggingInterest: Yes
GraphicsCard:
 Intel Corporation Haswell-ULT Integrated Graphics Controller [8086:0a2e] (rev 09) (prog-if 00 [VGA controller])
   Subsystem: Apple Inc. Haswell-ULT Integrated Graphics Controller [106b:0141]
InstallationDate: Installed on 2020-11-28 (520 days ago)
InstallationMedia: Ubuntu 20.04.1 LTS "Focal Fossa" - Release amd64 (20200731)
MachineType: Apple Inc. Macmini7,1
ProcEnviron:
 LANGUAGE=en_ZA:en
 TERM=xterm-256color
 PATH=(custom, no user)
 LANG=en_ZA.UTF-8
 SHELL=/bin/bash
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-5.15.0-27-generic root=UUID=278bd098-563c-4e88-85c7-d0dd2d492987 ro quiet splash vt.handoff=7
SourcePackage: xorg
Symptom: display
UpgradeStatus: Upgraded to jammy on 2022-04-29 (3 days ago)
dmi.bios.date: 09/16/2021
dmi.bios.release: 0.1
dmi.bios.vendor: Apple Inc.
dmi.bios.version: 432.40.8.0.1
dmi.board.asset.tag: Base Board Asset Tag#
dmi.board.name: Mac-35C5E08120C7EEAF
dmi.board.vendor: Apple Inc.
dmi.board.version: Macmini7,1
dmi.chassis.type: 10
dmi.chassis.vendor: Apple Inc.
dmi.chassis.version: Mac-35C5E08120C7EEAF
dmi.modalias: dmi:bvnAppleInc.:bvr432.40.8.0.1:bd09/16/2021:br0.1:svnAppleInc.:pnMacmini7,1:pvr1.0:rvnAppleInc.:rnMac-35C5E08120C7EEAF:rvrMacmini7,1:cvnAppleInc.:ct10:cvrMac-35C5E08120C7EEAF:skuSystemSKU#:
dmi.product.family: Mac
dmi.product.name: Macmini7,1
dmi.product.sku: System SKU#
dmi.product.version: 1.0
dmi.sys.vendor: Apple Inc.
version.compiz: compiz N/A
version.libdrm2: libdrm2 2.4.110-1ubuntu1
version.libgl1-mesa-dri: libgl1-mesa-dri 22.0.1-1ubuntu2
version.libgl1-mesa-glx: libgl1-mesa-glx N/A
version.xserver-xorg-core: xserver-xorg-core 2:21.1.3-2ubuntu2
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev N/A
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:19.1.0-2build3
version.xserver-xorg-video-intel: xserver-xorg-video-intel N/A
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.17-2build1

[Daniel van Vugt (vanvugt)]

Thanks for the bug report.

After you log in (any way possible) please run:

  journalctl -b0 > journal.txt

and then attach the resulting text file here.

[Daniel van Vugt (vanvugt)]

Please also check the other VTs: Ctrl+Alt+Fn
just to see if the login really worked but is starting on the wrong VT.

[Stapel (wstapelberg)]

I checked the other VTs: 1 takes me back to the GUI login. 2 gives me
nothing, just a black screen. 3 - 6 gives me a terminal login screen.

On Tue, May 3, 2022 at 4:55 AM Daniel van Vugt <email address hidden>
wrote:

> Please also check the other VTs: Ctrl+Alt+Fn
> just to see if the login really worked but is starting on the wrong VT.
>
> ** Package changed: xorg (Ubuntu) => mutter (Ubuntu)
>
> ** Changed in: mutter (Ubuntu)
> Status: New => Incomplete
>
> ** Also affects: xorg-server (Ubuntu)
> Importance: Undecided
> Status: New
>
> ** Changed in: xorg-server (Ubuntu)
> Status: New => Incomplete
>
> --
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/1971144
>
> Title:
> Black screen after login.
>
> To manage notifications about this bug go to:
>
> https://bugs.launchpad.net/ubuntu/+source/mutter/+bug/1971144/+subscriptions
>
>

[Stapel (wstapelberg)]

On Tue, May 3, 2022 at 9:58 AM wilhelm stapelberg <email address hidden>
wrote:

> I checked the other VTs: 1 takes me back to the GUI login. 2 gives me
> nothing, just a black screen. 3 - 6 gives me a terminal login screen.
>
> On Tue, May 3, 2022 at 4:55 AM Daniel van Vugt <email address hidden>
> wrote:
>
>> Please also check the other VTs: Ctrl+Alt+Fn
>> just to see if the login really worked but is starting on the wrong VT.
>>
>> ** Package changed: xorg (Ubuntu) => mutter (Ubuntu)
>>
>> ** Changed in: mutter (Ubuntu)
>> Status: New => Incomplete
>>
>> ** Also affects: xorg-server (Ubuntu)
>> Importance: Undecided
>> Status: New
>>
>> ** Changed in: xorg-server (Ubuntu)
>> Status: New => Incomplete
>>
>> --
>> You received this bug notification because you are subscribed to the bug
>> report.
>> https://bugs.launchpad.net/bugs/1971144
>>
>> Title:
>> Black screen after login.
>>
>> To manage notifications about this bug go to:
>>
>> https://bugs.launchpad.net/ubuntu/+source/mutter/+bug/1971144/+subscriptions
>>
>>

[Daniel van Vugt (vanvugt)]

Thanks for the log. I can't see anything that would explain a black screen, it looks normal.

Please try adding these to /etc/environment and then reboot:

  MUTTER_DEBUG_USE_KMS_MODIFIERS=0
  MUTTER_DEBUG_ENABLE_ATOMIC_KMS=0
  MUTTER_DEBUG_DISABLE_TRIPLE_BUFFERING=1

If that works then please also try to figure out which one exactly is fixing the problem.

[Stapel (wstapelberg)]

The three added lines to the /etc/environment file did not make a
difference. I tried both "Ubuntu" and "Ubuntu on Xorg" logins. I was
connected through a KVM to the monitor however, because I am sharing a
monitor, mouse and keyboard with other machines. So, I plugged a monitor in
directly (as well as a separate keyboard and mouse) and now I am able to
log in normally using either the "Ubuntu" or "Ubuntu on Xorg" logins. I
removed the three lines from the environment file again and login still
works. So it looks like 22.04 just does not like my KVM switch.

The KVM switch is a CKLau (CKLau-64HUA-UK).

On Tue, May 3, 2022 at 10:30 AM Daniel van Vugt <email address hidden>
wrote:

> Thanks for the log. I can't see anything that would explain a black
> screen, it looks normal.
>
> Please try adding these to /etc/environment and then reboot:
>
> MUTTER_DEBUG_USE_KMS_MODIFIERS=0
> MUTTER_DEBUG_ENABLE_ATOMIC_KMS=0
> MUTTER_DEBUG_DISABLE_TRIPLE_BUFFERING=1
>
> If that works then please also try to figure out which one exactly is
> fixing the problem.
>
> --
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/1971144
>
> Title:
> Black screen after login.
>
> To manage notifications about this bug go to:
>
> https://bugs.launchpad.net/ubuntu/+source/mutter/+bug/1971144/+subscriptions
>
>

[Daniel van Vugt (vanvugt)]

You will also need to reboot before /etc/environment changes take effect. But thanks for identifying the KVM issue.

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This change was made by a bot.

[Stapel (wstapelberg)]

This has now been fixed. After installing the latest updates, I tried the setup with the KVM switch again, and it worked.

[Daniel van Vugt (vanvugt)]

OK then, fix released... somewhere.

[Stapel (wstapelberg)]

The problem is back again. I have not used it for about 1 week, and when I tried to log in now, the same problem was back again.