1708282 - Subpixel font rendering not working in Firefox 89 beta on Linux

Status: RESOLVED DUPLICATE of bug 1708285

(Core :: Layout: Text and Fonts, defect)

Description

[Michael Marley]

User Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:89.0) Gecko/20100101 Firefox/89.0

Steps to reproduce:

I upgraded from Firefox 88 to Firefox 89 beta on Linux (Specifically, Kubuntu 21.04 with xorg).

Actual results:

Subpixel font rendering stopped working on all web content. Only grayscale font rendering is used instead. This started happening after upgrading to Firefox 89 beta; Firefox 88 is unaffected. The nightly build from today (4/28/2021) also has the issue. It happens regardless of whether I am using WebRender or not. Creating a fresh profile has no effect.

I have no systems to test Windows or Mac, I don't know if this issue affects them as well.

Expected results:

Subpixel font rendering should continue to work correctly.

Comment 1

[Michael Marley]

The issue also seems to affect only web content; the address bar still seems to be using subpixel rendering.

Comment 2

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

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

Comment 3

[Michael Marley]

I was able to find a Windows system on which to test and found that the problem does NOT affect Firefox 89 beta on Windows, so it seems to be Linux-specific.