Rendering is delayed on laptop display (works in external display)

[Daniele Dellafiore]

This is a very wierd behavior I get on the Lenovo Yoga S940 after upgrading to 19.10.
This makes the laptop almost unusable with its own display.
This happens only on the laptop display, not on the external display.

The render of portions of the screen does not happen after some events (listed below) resulting in all or part of the screen not being re-rendered. The UX is that nothing happened, but it has.
This happens after:

* key-stroke while typing sometimes
* alt-tab
* shift-right to align window to the right
* ctrl-pgup/down to switch tab in multi tabs apps.

Please note that:
* screenshots can't see the problem
* also screenrecorder always seem ok, despite rendering being broken.

ProblemType: Bug
DistroRelease: Ubuntu 19.10
Package: xorg 1:7.7+19ubuntu12
ProcVersionSignature: Ubuntu 5.3.0-13.14-generic 5.3.0
Uname: Linux 5.3.0-13-generic x86_64
ApportVersion: 2.20.11-0ubuntu7
Architecture: amd64
BootLog: Error: [Errno 13] Permission denied: '/var/log/boot.log'
CompositorRunning: None
CurrentDesktop: ubuntu:GNOME
Date: Tue Oct 1 13:13:40 2019
DistUpgraded: 2019-09-21 10:16:26,647 DEBUG Running PostInstallScript: './xorg_fix_proprietary.py'
DistroCodename: eoan
DistroVariant: ubuntu
ExtraDebuggingInterest: Yes, including running git bisection searches
GraphicsCard:
 Intel Corporation UHD Graphics 620 (Whiskey Lake) [8086:3ea0] (rev 02) (prog-if 00 [VGA controller])
   Subsystem: Lenovo UHD Graphics 620 (Whiskey Lake) [17aa:3801]
InstallationDate: Installed on 2019-09-12 (18 days ago)
InstallationMedia: Ubuntu 19.04 "Disco Dingo" - Release amd64 (20190416)
MachineType: LENOVO 81Q7
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-5.3.0-13-generic root=/dev/mapper/ubuntu--vg-root ro quiet splash vt.handoff=7
SourcePackage: xorg
Symptom: display
UpgradeStatus: Upgraded to eoan on 2019-09-21 (10 days ago)
dmi.bios.date: 06/12/2019
dmi.bios.vendor: LENOVO
dmi.bios.version: AKCN34WW
dmi.board.asset.tag: No Asset Tag
dmi.board.name: LNVNB161216
dmi.board.vendor: LENOVO
dmi.board.version: SDK0J40709 WIN
dmi.chassis.asset.tag: No Asset Tag
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: Lenovo Yoga S940-14IWL
dmi.modalias: dmi:bvnLENOVO:bvrAKCN34WW:bd06/12/2019:svnLENOVO:pn81Q7:pvrLenovoYogaS940-14IWL:rvnLENOVO:rnLNVNB161216:rvrSDK0J40709WIN:cvnLENOVO:ct10:cvrLenovoYogaS940-14IWL:
dmi.product.family: Yoga S940-14IWL
dmi.product.name: 81Q7
dmi.product.sku: LENOVO_MT_81Q7_BU_idea_FM_Yoga S940-14IWL
dmi.product.version: Lenovo Yoga S940-14IWL
dmi.sys.vendor: LENOVO
version.compiz: compiz N/A
version.libdrm2: libdrm2 2.4.99-1ubuntu1
version.libgl1-mesa-dri: libgl1-mesa-dri 19.1.6-1ubuntu1
version.libgl1-mesa-glx: libgl1-mesa-glx N/A
version.xserver-xorg-core: xserver-xorg-core 2:1.20.5+git20190820-0ubuntu3
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev N/A
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:19.0.1-1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.917+git20190815-1
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.16-1

[Daniele Dellafiore (ildella)]

Update.
Today I experienced this: after suspending the laptop, now I do not experience broken rendering anymore.
This happened once before. Everytime I reboot, it comes back.

I'll try to identify a pattern here.

[Daniele Dellafiore (ildella)]

Update.
Today I experienced this: after suspending the laptop, now I do not experience broken rendering anymore.
This happened once before. Everytime I reboot, it comes back.

I'll try to identify a pattern here.

Also this is in the "Tweaks" application, gnome-shell does not have a theme associated (see screenshot)

[Daniele Dellafiore (ildella)]

I've made a picture as screenrecord/screenshot can't cath the problem.
As you can see the render is still on "General" despite "Extensions" being the current selection.
You can see at the top part of the rendering is restarted and is now stuck in the middle.

[Daniel van Vugt (vanvugt)]

I've never seen this problem before. The only unusual thing I can see is that you have a shiny new Whiskey Lake GPU, which means it's a newish graphics driver path.

Can you please make a video of the problem on a phone or camera?

[Daniel van Vugt (vanvugt)]

Also, does the bug occur if you log into 'Ubuntu on Wayland' ?

[Daniel van Vugt (vanvugt)]

Possibly also related - Xrandr.txt strangely doesn't list any viewport dimensions for the laptop display eDP-1.

[Daniele Dellafiore (ildella)]

Ubuntu on Wayland has same behavior, but worst.

Video attached shows open a new tab with CTRL+T and the new tab not being rendered until I create a new.
Then I remove both, I create a new one, not rendered, and got rendered only when the mouse is moved.
https://photos.app.goo.gl/6Nc6oABXs1xX1ks26

This worked fine in 19.04 and works fine now with external display.

I'll send another video showing how windows animation for align right/left do not work, windows just step from one state to the next with no animation.
Minimize/maximize are perfect.

[Daniel van Vugt (vanvugt)]

I wonder if the delay is equal to the number of buffers' whose damage mutter is tracking... What this means is that it could take 3 or 4 frames to update everything. I've seen reports of such issues in mutter 3.34, like bug 1845623.

If you have a separate window animating in the corner of the screen (glxgears or a video) then does that work around the problem? How about if you have a maximized window constantly updating underneath?

[Daniele Dellafiore (ildella)]

wow, yes, it does!

[Daniele Dellafiore (ildella)]

I mean, the video aligned right fixes the problem

[Daniel van Vugt (vanvugt)]

OK, this sounds like a mutter bug... unless that weirdness in your Xrandr.txt is related:

  eDP-1 connected (normal left inverted right x axis y axis)
  ...
  DP-1 connected primary 2560x1440+0+0 (0x152) normal (normal left inverted right x axis y axis) 600mm x 340mm

This means the desktop is arranged primarily to fit your external monitor (DP-1) but the built-in screen (eDP-1) has no known position. So it may not update properly. This is too suspicious to ignore so would be the first thing for someone to look at.

[Daniel van Vugt (vanvugt)]

Thank you for reporting this bug to Ubuntu.
Ubuntu 19.10 (eoan) reached end-of-life on July 17, 2020.

See this document for currently supported Ubuntu releases:
https://wiki.ubuntu.com/Releases

We appreciate that this bug may be old and you might not be interested in discussing it any more. But if you are then please upgrade to the latest Ubuntu version and re-test. If you then find the bug is still present in the newer Ubuntu version, please add a comment here telling us which new version it is in and change the bug status to Confirmed.