Comment 47 for bug 2060268

I'm not using encryption or zfs and the bug has been present since the beta

On Sun, Jun 16, 2024, 9:05 PM Sidney Kelley <email address hidden>
wrote:

> > I also have encryption, does everyone with the bug have it?
>
>
> Nope. I just got my bug marked duplicate here. I am not running
> encryption, but I am running ZFS, which uses a vaguely similar disk
> abstraction (booting a "fake" device that "maps" to a real one in some
> arbitrary way).
>
> However, my bug was solved when I installed kubuntu-desktop (and then
> switched the default display manager back to gdm3). So, I assume one of
> the dependencies it brought along fixed it.
>
> --
> You received this bug notification because you are subscribed to a
> duplicate bug report (2063222).
> https://bugs.launchpad.net/bugs/2060268
>
> Title:
> Phantom "Unknown Display" shown in Settings after installing the
> Nvidia driver
>
> Status in linux package in Ubuntu:
> Confirmed
> Status in nvidia-graphics-drivers-470 package in Ubuntu:
> Confirmed
> Status in nvidia-graphics-drivers-535 package in Ubuntu:
> Confirmed
> Status in nvidia-graphics-drivers-545 package in Ubuntu:
> Confirmed
> Status in nvidia-graphics-drivers-550 package in Ubuntu:
> Confirmed
>
> Bug description:
> [ Impact ]
>
> After installing Nvidia driver 545 on a single (27") monitor system,
> Settings shows a phantom 46" monitor of the same resolution.
>
> It looks like the phantom monitor is /dev/dri/card0 which is still
> controlled by simpledrm, while Nvidia uses /dev/dri/card1.
>
> [ Temporary Workaround ]
>
> 1. sudo rm /dev/dri/card0
> 2. Log in again.
>
> [ Permanent Workaround ]
>
> Add kernel parameter:
> initcall_blacklist=simpledrm_platform_driver_init
>
> [ Test Plan ]
>
> Open Settings and verify the only monitors shown are your real
> monitors.
>
> [ Where problems could occur ]
>
> Removing the simpledrm card is only safe when it's not being used. If
> somehow a machine wasn't using the installed Nvidia driver then there
> could be a risk of deleting the only working display.
>
> [ Other Info ]
>
> ProblemType: Bug
> ApportVersion: 2.28.0-0ubuntu1
> Architecture: amd64
> AudioDevicesInUse:
> USER PID ACCESS COMMAND
> /dev/snd/seq: dan 4631 F.... pipewire
> /dev/snd/controlC1: dan 4636 F.... wireplumber
> CRDA: N/A
> CasperMD5CheckResult: pass
> DistroRelease: Ubuntu 24.04
> InstallationDate: Installed on 2024-01-04 (92 days ago)
> InstallationMedia: Ubuntu 24.04 "Noble Numbat" - Daily amd64 (20231127)
> MachineType: Intel(R) Client Systems NUC12DCMi7
> NonfreeKernelModules: nvidia_modeset nvidia
> Package: linux (not installed)
> ProcEnviron:
> LANG=en_US.UTF-8
> PATH=(custom, no user)
> SHELL=/bin/bash
> TERM=xterm-256color
> XDG_RUNTIME_DIR=<set>
> ProcFB: 0 simpledrmdrmfb
> ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-6.8.0-11-generic
> root=UUID=8434774e-88f2-4e3f-adb8-2eb07dff3cf9 ro quiet loglevel=3 splash
> vt.handoff=7
> ProcVersionSignature: Ubuntu 6.8.0-11.11-generic 6.8.0-rc4
> RelatedPackageVersions:
> linux-restricted-modules-6.8.0-11-generic N/A
> linux-backports-modules-6.8.0-11-generic N/A
> linux-firmware 20240318.git3b128b60-0ubuntu1
> Tags: noble
> Uname: Linux 6.8.0-11-generic x86_64
> UpgradeStatus: No upgrade log present (probably fresh install)
> UserGroups: adm cdrom dip lpadmin plugdev sudo users
> _MarkForUpload: True
> dmi.bios.date: 12/20/2021
> dmi.bios.release: 5.24
> dmi.bios.vendor: Intel Corp.
> dmi.bios.version: EDADL579.0046.2021.1220.2351
> dmi.board.name: NUC12EDBi7
> dmi.board.vendor: Intel Corporation
> dmi.board.version: M27908-302
> dmi.chassis.type: 35
> dmi.chassis.vendor: Intel Corporation
> dmi.chassis.version: 2.0
> dmi.ec.firmware.release: 3.7
> dmi.modalias:
> dmi:bvnIntelCorp.:bvrEDADL579.0046.2021.1220.2351:bd12/20/2021:br5.24:efr3.7:svnIntel(R)ClientSystems:pnNUC12DCMi7:pvrM30143-302:rvnIntelCorporation:rnNUC12EDBi7:rvrM27908-302:cvnIntelCorporation:ct35:cvr2.0:skuRNUC12DCMi70000:
> dmi.product.family: DC
> dmi.product.name: NUC12DCMi7
> dmi.product.sku: RNUC12DCMi70000
> dmi.product.version: M30143-302
> dmi.sys.vendor: Intel(R) Client Systems
>
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>
>