1723371 - KDE/X11/Nvidia PRIME: Screen tearing with NVidia Webrender

Status: RESOLVED WORKSFORME

(Core :: Graphics: WebRender, defect)

Description

[Lyubomir [:mystiquewolf]]

User Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:90.0) Gecko/20100101 Firefox/90.0

Steps to reproduce:

Just scrolling

Actual results:

Please see screencast for the lines during scrolling here: https://youtu.be/sgAafxckO6o

Expected results:

No lines during scrolling

Comment 1

[BugBot [:suhaib / :marco/ :calixte]]

The Bugbug bot thinks this bug should belong to the 'Core::Graphics: WebRender' component, and is moving the bug to that component. Please revert this change in case you think the bot is wrong.

Comment 2

[Darkspirit]

Thanks for the report! I don't see any tearing in the video.

Can this be fixed by the following steps?

1. Open Nvidia X Server Settings > X Server Display Configuration > Advanced
2. Enable "Force Full Composition Pipeline"
3. "Apply"
4. "Save to X Configuration File"

Please also remove the MOZ_ENABLE_WAYLAND=1 environment variable. You are using KDE/X11.

Comment 3

[Lyubomir [:mystiquewolf]]

Well this is pretty strange. I also don't see any tearing in the video.

To start with, i don't know if the name for my problem is tearing or some other GPU-nerdy word. Basically it's like there's a line which only appears upon scroll, whose width is from the left edge to the right edge of my screen. This line has a height about 10-15 centimeters. If you divide the screen height in roughly 10 equal height lines/parts, this "tearing line" is the third counted from the top. Inside this 10-15 centimeters height line, the text looks like it's magnified and a little bit blurry. It looks exactly like a wave in an ocean. I don't know how to describe it with other words.

Even more strange is that when i was using NVidia driver it was visible both in Firefox page and in the video in VLC player. But then i disabled NVidia and enabled Intel, tested for the issue on the page and it didn't appear. Then upon your response that you can't see it in the video i again switched to NVidia and the difference is that this time i can't see it neither in the video nor reproduce in the Firefox page.

This is not the first time i've experienced this issue with NVidia, i've also experienced it other times with regular pages like Wikipedia for example. But didn't report it then. Just used Intel because it keeps the laptop colder and doesn't have this issue. And in fact Webrender was listed on Mozilla Wiki as not supported with NVidia at that time.

Comment 4

[Lyubomir [:mystiquewolf]]

In addittion, i don't have this option in NVidia settings called "Force Full Composition Pipeline". Actually clicking "Advanced" doesn't show any more settings that the "basic" view shows.

Comment 5

[Lyubomir [:mystiquewolf]]

Attachment: 2021-08-01_17-58.png

Comment 6

[Darkspirit]

Would setting nvidia-drm.modeset=1 help? https://askubuntu.com/a/1266161
(https://wiki.archlinux.org/title/NVIDIA/Troubleshooting#Avoid_screen_tearing_in_KDE_(KWin))

Comment 7

[Lyubomir [:mystiquewolf]]

I'm not sure that this can still be reproduced. If it does it is so subtle that i'm questioning myself whether it reproduces or it doesn't.
That said, i believe that it can be seen on the video above at/around 1 second into the video (the moment it starts to move) - around Remote Features, that i believe is the location where it can be seen, but i might be only "imaginating". Plus maybe the waving effect can be seen in the video at the place where the letters hide from screen during scroll (that is the top edge line of the viewport), but way more subtler than the effect i saw back then.

I don't believe this bug is actionable as i can't really reproduce it now, although i'm sure it happened more than once back in the time. You can close it.