MATE desktop in Ubuntu 20.04 screen tearing with modeset driver

[arno]

Running a Ubuntu 20.04 with its default (kmodesetting ?) driver. Screen tearing is present and shows artefacts while scrolling in browsers (firefox and chromium) and videos.

Ubuntu 5.4.0-40.44-generic 5.4.44

Processor/GPU is a core m5-6y54 (Skylake)
---
ProblemType: Bug
ApportVersion: 2.20.11-0ubuntu27.4
Architecture: amd64
BootLog: Error: [Errno 13] Keine Berechtigung: '/var/log/boot.log'
CasperMD5CheckResult: skip
CompositorRunning: None
CurrentDesktop: MATE
DistUpgraded: Fresh install
DistroCodename: focal
DistroRelease: Ubuntu 20.04
DistroVariant: ubuntu
ExtraDebuggingInterest: Yes, if not too technical
GraphicsCard:
 Intel Corporation HD Graphics 515 [8086:191e] (rev 07) (prog-if 00 [VGA controller])
   Subsystem: Hewlett-Packard Company HD Graphics 515 [103c:8170]
InstallationDate: Installed on 2020-05-10 (78 days ago)
InstallationMedia: Ubuntu-MATE 20.04 LTS "Focal Fossa" - Release amd64 (20200423)
Lsusb:
 Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
 Bus 001 Device 003: ID 8087:0a2b Intel Corp.
 Bus 001 Device 002: ID 04f2:b560 Chicony Electronics Co., Ltd HP HD Camera
 Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
MachineType: HP HP EliteBook Folio G1
Package: xorg-server (not installed)
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-5.4.0-42-generic root=UUID=92c467dc-e394-4f19-a6a2-e7cf918f0ffb ro quiet splash vt.handoff=7
ProcVersionSignature: Ubuntu 5.4.0-42.46-generic 5.4.44
Tags: focal ubuntu
Uname: Linux 5.4.0-42-generic x86_64
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm cdrom dip lpadmin lxd plugdev sambashare sudo
_MarkForUpload: True
dmi.bios.date: 01/05/2020
dmi.bios.vendor: HP
dmi.bios.version: N91 Ver. 01.45
dmi.board.name: 8170
dmi.board.vendor: HP
dmi.board.version: KBC Version 29.73
dmi.chassis.type: 10
dmi.chassis.vendor: HP
dmi.modalias: dmi:bvnHP:bvrN91Ver.01.45:bd01/05/2020:svnHP:pnHPEliteBookFolioG1:pvr:rvnHP:rn8170:rvrKBCVersion29.73:cvnHP:ct10:cvr:
dmi.product.family: 103C_5336AN
dmi.product.name: HP EliteBook Folio G1
dmi.product.sku: V1C39EA#ABD
dmi.sys.vendor: HP
version.compiz: compiz N/A
version.libdrm2: libdrm2 2.4.101-2
version.libgl1-mesa-dri: libgl1-mesa-dri 20.0.8-0ubuntu1~20.04.1
version.libgl1-mesa-glx: libgl1-mesa-glx N/A
version.xserver-xorg-core: xserver-xorg-core 2:1.20.8-2ubuntu2.2
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev N/A
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:19.1.0-1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.917+git20200226-1
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.16-1

[Ubuntu Foundations Team Bug Bot (crichton)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. It seems that your bug report is not filed about a specific source package though, rather it is just filed against Ubuntu in general. It is important that bug reports be filed about source packages so that people interested in the package can find the bugs about it. You can find some hints about determining what package your bug might be about at https://wiki.ubuntu.com/Bugs/FindRightPackage. You might also ask for help in the #ubuntu-bugs irc channel on Freenode.

To change the source package that this bug is filed about visit https://bugs.launchpad.net/ubuntu/+bug/1888810/+editstatus and add the package name in the text box next to the word Package.

[This is an automated message. I apologize if it reached you inappropriately; please just reply to this message indicating so.]

[Sebastien Bacher (seb128)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. Please execute the following command, as it will automatically gather debugging information, in a terminal:

  apport-collect 1888810

When reporting bugs in the future please use apport by using 'ubuntu-bug' and the name of the package affected. You can learn more about this functionality at https://wiki.ubuntu.com/ReportingBugs.

[arno (star-gmx)]

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[arno (star-gmx)]

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[Daniel van Vugt (vanvugt)]

This could be one of a number of bugs.

If you are using the old 'intel' driver then it's bug 1867668.

If you are using multiple monitors then it's bug 1853094.

If you are using fullscreen apps then it's bug 1754284.

If none of the above then this should probably move to the window manager ("marco"?).

[arno (star-gmx)]

Mh, tearing seems to be a widespread issue. Regarding the duplicates:
- I am not using intel driver but modesetting driver.
- Don't have a second screen active.
- Tearing is not limited to full screen applications.

Yes, "marco" is Mate window manager. Does your answer mean that marco is the source of problem?
What I can observer is that loading the intel-driver (with set tearfree option) the problem disappears. My guess this means it is not a issue or "marco", right?
But of course there is a reason that ubuntu uses the modesetting instead of intel per default, that on cause other issues :(

[Daniel van Vugt (vanvugt)]

The driver name 'intel' is the cause of some confusion. It sounds like the right driver but actually it's old and not usually recommended. It has some bugs that the new generic driver ('modeset') does not. However 'intel' does indeed have the TearFree option which 'modeset' does not yet: https://gitlab.freedesktop.org/xorg/xserver/-/issues/244

We already have a couple of bugs sharing that upstream bug link so I guess this can be another one.

[arno (star-gmx)]

You nailed it: intel hardware (this is what I refered), but modeset driver. Topic is clearer now - thanks. Age of bug is rather old, not a good sign imho.

[Daniel van Vugt (vanvugt)]

I think it's a result of Wayland's growing popularity, particularly upstream and other distros where it is default. There are much fewer developers involved in fixing Xorg now.

[arno (star-gmx)]

True but on the other hand this (Ubuntu 20.04) are LTS distros. This will affect poeple at least for more than 3 years. But I understand, the new stuff (Wayland) is more of interest for dev than fixing the old one.

[Daniel van Vugt (vanvugt)]

Looking deeper at this bug I just noticed the issue is triggered by using a fake screen resolution:

  1912x1080_60.00 (0x48) 171.250MHz -HSync +VSync *current +preferred

It should be 1920x1080 (https://support.hp.com/au-en/document/c05033206#AbT3).

While Xorg lets you create any resolution of your choice, doing so will result in indirect rendering, which will result in tearing with the modeset driver.

So this bug seems like user error... You just need to remove the custom mode "1912x1080" or find out what/where that came from.

[arno (star-gmx)]

You are right, but I am using this strange resolution with a good reason. If I am using 1920x1080 I am suffered from a even bigger bug - after resume (which often happens with laptops) the screen flickers like hell.

See here:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1872760

Playing around with resolution and framerates I found that it doesn't flicker in any other resolution but 1920x1080. That's why I created this custom one. Didn't expect this dependency on tearing.

[Daniel van Vugt (vanvugt)]

Sorry to hear about that other bug.

To avoid confusion and unnecessary duplication I have now generalized bug 1846398 so it covers this issue too.