User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Firefox/91.0

Steps to reproduce:

Today I updated Firefox Developer edition.

Actual results:

After restart all tabs are failing to open (crashed all tabs, even new tab) - I solved issue by resetting webrender and xrender variables in config however after that window became 50% transparent and blurry. I am on Ubuntu 20.04 with Nvidia 460 driver. Have GeForce MX230. Here is a picture of what is happening: https://i.imgur.com/PxegBUy.png
Now I can not use Firefox at all, please help resolve this!

Expected results:

Firefox working normally.

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

Can you try to use mozregression to find broken commit?
https://fedoraproject.org/wiki/How_to_debug_Firefox_problems?rd=Bug_info_Firefox#Use_Mozregression_tool

Also please try latest nightly with clean profile:
https://fedoraproject.org/wiki/How_to_debug_Firefox_problems?rd=Bug_info_Firefox#Testing_Mozilla_binaries

Thanks.

Thank you for response, Martin, I unfortunately can not find any commit that could've broke it, problem reproduces on even versions below 80. Good chance that it is just Nvidia drivers are broken or something like that. However - after running nightly build with both clean and my main profile everything works fine with xrender enabled, no tabs are crashing. Without xrender enabled there is still alpha (transparency) issues even on nightly build.

(In reply to q3.max.2011 from comment #3)

However - after running nightly build with both clean and my main profile everything works fine with xrender enabled, no tabs are crashing. Without xrender enabled there is still alpha (transparency) issues even on nightly build.

The crash has been bug 1719668.

Please disable xrender, restart Nightly, open about:support, click on the "copy text to clipboard" button and paste it here. Thanks!

It Nightly still transparent if you launch it with e.g.
$ MOZ_GTK_TITLEBAR_DECORATION=none ~/Downloads/firefox-nightly/firefox
or
$ MOZ_GTK_TITLEBAR_DECORATION=system ~/Downloads/firefox-nightly/firefox
?

Do you actually need deprecated xrender? It disables WebRender hardware rendering and only makes sense if you insecurely use some X session with Firefox over the network. (X11 Forwarding doesn't transmit the desktop as a regular video stream like good remote desktop applications do.)

Do you actually need deprecated xrender?
Well, right now no, but I do forward my X11 sometimes and it is very useful to be able to open Firefox trough.

It Nightly still transparent if you launch it with MOZ_GTK_TITLEBAR_DECORATION

With both none and system it is still transparent but now inside window.

Please open NVIDIA X Server Settings > X Screen 0 > Antialiasing Settings and check if you have manually enabled FXAA. It could be the cause. (bug 1714483)

Yep, that is exactly what was causing issue, thank you.

Thanks for the confirmation!

(In reply to q3.max.2011 from bug 1714483 comment 19)

After another update it is now broken even without FXAA enabled, how can this be debugged?

You could try to find a regression range if there is any:
$ pip3 install mozregression
$ mozregression --good 2021-02-01 --bad 2021-07-17 --pref gfx.webrender.all:true
Or go even further back. You can also directly launch dates to try around:
$ mozregression --launch YYYY-MM-DD --pref gfx.webrender.all:true