GDM horizontal scanline corruption with an ultra wide monitor

[APolihron]

Using a ultra wide monitor with ubuntu 18.04 daily it's a bad ideea. Because the loging screen it's out of focus and has orizontal radio screen lines

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: gdm3 3.26.2.1-2ubuntu2
ProcVersionSignature: Ubuntu 4.13.0-32.35-generic 4.13.13
Uname: Linux 4.13.0-32-generic x86_64
ApportVersion: 2.20.8-0ubuntu8
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Mon Feb 12 13:28:04 2018
InstallationDate: Installed on 2018-02-12 (0 days ago)
InstallationMedia: Ubuntu 18.04 LTS "Bionic Beaver" - Alpha amd64 (20180212)
SourcePackage: gdm3
UpgradeStatus: No upgrade log present (probably fresh install)

[Daniel van Vugt (vanvugt)]

We can't seem to be able to see the problem you're describing. Can you provide a clearer photo?

[APolihron (apolitech)]

I wish. The problem its because the screen is blurry my iPhone won’t focus

În mar., 13 feb. 2018 la 05:00 Daniel van Vugt <
<email address hidden>> a scris:

> We can't seem to be able to see the problem you're describing. Can you
> provide a clearer photo?
>
> ** Changed in: gdm3 (Ubuntu)
> Status: New => Incomplete
>
> --
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/1748871
>
> Title:
> gdm with a ultra wide monitor it's soo bad
>
> Status in gdm3 package in Ubuntu:
> Incomplete
>
> Bug description:
> Using a ultra wide monitor with ubuntu 18.04 daily it's a bad ideea.
> Because the loging screen it's out of focus and has orizontal radio
> screen lines
>
> ProblemType: Bug
> DistroRelease: Ubuntu 18.04
> Package: gdm3 3.26.2.1-2ubuntu2
> ProcVersionSignature: Ubuntu 4.13.0-32.35-generic 4.13.13
> Uname: Linux 4.13.0-32-generic x86_64
> ApportVersion: 2.20.8-0ubuntu8
> Architecture: amd64
> CurrentDesktop: ubuntu:GNOME
> Date: Mon Feb 12 13:28:04 2018
> InstallationDate: Installed on 2018-02-12 (0 days ago)
> InstallationMedia: Ubuntu 18.04 LTS "Bionic Beaver" - Alpha amd64
> (20180212)
> SourcePackage: gdm3
> UpgradeStatus: No upgrade log present (probably fresh install)
>
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/ubuntu/+source/gdm3/+bug/1748871/+subscriptions
>

[APolihron (apolitech)]

hmm here is a video https://www.youtube.com/watch?v=m_9jOU0t_2w

[Daniel van Vugt (vanvugt)]

Thanks. That looks like a bug in the mutter code, which provides the graphics back-end.

Please log the bug here: https://gitlab.gnome.org/GNOME/mutter/issues
and then tell us the ID of the newly-created bug.

[Daniel van Vugt (vanvugt)]

Done.

https://gitlab.gnome.org/GNOME/mutter/issues/40

[e3b0c442 (e3b0c442)]

I can also verify this issue.

A few things to further note (just in case there may be other involved components):

1) This issue also affects Ubuntu 17.10 out of the box, as well as Fedora 27.
2) The issue is not just with the login screen; this "vertical asynchronization" is also present during bootup, as well as during the desktop session if logged in. (It is even present during boot with Ubuntu 16.04, which I clean-installed when I encountered this issue initially with 17.10 after purchasing my ultrawide monitor)
3) The issue is not present if I am able to change the resolution to 1920x1080 (of course, this negates the benefit of the ultrawide monitor)
4) If it weren't for it also being present during the bootup sequence, I would say that it seems to be constrained to Wayland; if Wayland is disabled, the issue is not present at the login screen nor during the desktop session.

I understand this makes pinning the culprit down more difficult; if it weren't for everything working fine in X.org, I would point the finger at the AMDGPU driver. If it weren't for the issue being present during the bootup sequence, I would point the finger at Wayland.

[Daniel van Vugt (vanvugt)]

Thanks Nick.

If you or someone can provide a video/photo of the issue occurring during boot up then we could confidently reassign this to the kernel instead of Gnome.

[APolihron (apolitech)]

With the new kernel this problem is gone in 18.04 daily. Can someone test
it?

În mar., 27 feb. 2018 la 03:51 Daniel van Vugt <
<email address hidden>> a scris:

> Thanks Nick.
>
> If you or someone can provide a video/photo of the issue occurring
> during boot up then we could confidently reassign this to the kernel
> instead of Gnome.
>
> --
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/1748871
>
> Title:
> GDM horizontal scanline corruption with an ultra wide monitor
>
> Status in gdm3 package in Ubuntu:
> New
> Status in mutter package in Ubuntu:
> New
>
> Bug description:
> Using a ultra wide monitor with ubuntu 18.04 daily it's a bad ideea.
> Because the loging screen it's out of focus and has orizontal radio
> screen lines
>
> ProblemType: Bug
> DistroRelease: Ubuntu 18.04
> Package: gdm3 3.26.2.1-2ubuntu2
> ProcVersionSignature: Ubuntu 4.13.0-32.35-generic 4.13.13
> Uname: Linux 4.13.0-32-generic x86_64
> ApportVersion: 2.20.8-0ubuntu8
> Architecture: amd64
> CurrentDesktop: ubuntu:GNOME
> Date: Mon Feb 12 13:28:04 2018
> InstallationDate: Installed on 2018-02-12 (0 days ago)
> InstallationMedia: Ubuntu 18.04 LTS "Bionic Beaver" - Alpha amd64
> (20180212)
> SourcePackage: gdm3
> UpgradeStatus: No upgrade log present (probably fresh install)
>
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/ubuntu/+source/gdm3/+bug/1748871/+subscriptions
>

[APolihron (apolitech)]

On the 18.04 daily with the new kernel this problem is gone. Can someone test it?

[Daniel van Vugt (vanvugt)]

Yes when the problem was first reported we had kernel 4.13, but now it is 4.15 which might have fixed it.

Since you are the original reporter we can declare this bug fixed. Anyone else who still has issues after updating to kernel 4.15 should file a new bug.