Fixing Firefox screen tearing while scrolling / video playback

For a while now I’ve noticed screen tearing while scrolling on Wikipedia or on YouTube videos whenever there’s sudden movement.

Today I decided to do something about it, and considering I hadn’t touch the Xorg conf files “generated” by nvidia-xconfig in more than 4 years, I was optimistic that it would be some configuration issue that would have been automatically resolved by now with newer drivers and OpenGL versions. Furthermore as the quotes on generated suggest, they weren’t pristine generated Xorg conf files since I had tinkered with them quite a bit in the past when I was running two Nvidia cards on Arch which I mentioned in passing in a previous post

So the first thing I did was generate a new Xorg conf, using the command:

$ nvidia-xconfig

Which graciously backups the previous config and generates a new one in its stead.

Having done that I rebooted the computer, opened Firefox and scrolled some long articles in Wikipedia (like the one for the current Covid-19 Pandemic) but the tearing was still there.

So I searched the web and found this post on reddit which basically describes exactly what was happening to me.

In it there are basically two solutions provided by the community:

  1. Force GPU Acceleration on Firefox

  2. Force Full Composition Pipeline of the Nvidia card.

The first one was self explanatory and the simplest, besides if you have the hardware you would want to use it whenever and wherever you can, specially in a desktop environment, where you’re not restricted by power consumption from a battery.

As for the second option, from the comments and after looking into the good ole trusty Arch Wiki for screen tearing on nvidia, it seems that while this does avoid screen tearing not just in Firefox but in every application, it comes with a performance penalty in OpenGL applications as well as increasing the time needed for the GPU to “clock down” i.e: bring its frequency back down due to changing power states after some rendering task is finished.

Since in my case I’ve only noticed the screen tearing in Firefox, it seemed like a no-brainer opt for this approach.

To change I simply needed to go to the advanced preferences page of Firefox reached by navigating to about:config in the browser, search for layers.acceleration.force-enabled, set it to true and restart Firefox.

VoilĂ .

Side note: The reason why GPU Acceleration is disabled by default in Firefox on most, if not all Linux distributions is because WebGL is considered by many as a security risk. For more a detailed explanation check this security.stackexchange answer

Last modified on 2020-05-04

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