Description

Tried to install Ubuntu 20.04 on an old computer that is quad core Intel and contains an Q33 integrated video from intel.
Normally people install linux on old computers so they can keep using it for basic stuff.
The system has a clean install but saw glitches when using Firefox. (see video attached)
half of the screen is not in synch with the other half when i scroll up and down.

Tested on
Ubuntu 20.04 affected
Windows10 64bit not affected (but used another video card)
MacOs 10.15 not affected (but used another video card)

Using
FX release79 affected
FX 80.0b4 affected
FX 81.0a1 affected

steps one of the glitches:

• launch firefox and visit https://itsfoss.com/record-screen-ubuntu-simplescreenrecorder/
• scroll down and up.

other glitches found

• Launch firefox with clean profile.
• on second tab to to about:config and set browser.search.widget.inNavBar to true.
• on a third tab go to about:profiles, and click restart normally, then check top right area of firefox

actual result
glitches on screen

expected result
should not show glitches.

notes: (i installed Chromium and such glitches were not visible) on Ubuntu 20.04

might be severity S4

That's tearing and expected with software rendering (Basic compositor): bug 1420712.
For most users it will be fixed by WebRender rollout: bug 1614523.
Please open about:config, set gfx.webrender.all to true, restart Firefox, open about:support, click on "Copy text to clipboard" and paste it here. Thanks!

done! attached the file. let me know if you need anything else.
thanks

It seems Intel Q33 supports OpenGL 1.4 at maximum, therefore it will never be hardware accelerated.
Could you type gfx.webrender.software into the search box on about:config, add it as new boolean pref, set it true, restart Firefox and copy its about:support page? How does Software WebRender (bug 1601053) perform, do you notice any difference and do you see the same glitch?

Marking this as wontfix as there is not much we can do about tearing on non-accelerated platforms.