1938753 - Window Device Pixel Ratios incorrectly set on Swaywm in Nightly 135.0a1 20241218012535

Status: RESOLVED DUPLICATE of bug 1943583

(Core :: Widget: Gtk, defect, P3)

Description

[Christopher]

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:135.0) Gecko/20100101 Firefox/135.0

Steps to reproduce:

I have a 4k monitor with a 2x scale factor set in Swaywm under Arch linux

output DP-2 pos 1920 0 mode 3840x2160@60Hz scale 2 in sway config

I update firefox to Nightly 135.0a1 build ID 20241218012535 from build ID 20241215043337 (which works as expected)

I launch firefox with MOZ_ENABLE_WAYLAND=1

Actual results:

Text rendering is poor, and under about:support "Window Device Pixel Ratios" shows a value of 1

Expected results:

Text rendering is clear and "Window Device Pixel Ratios" is set to 2

Comment 1

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

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

Comment 2

[Christopher]

I used Mozregression to bisect this issue, and I believe the commit that caused this change was https://phabricator.services.mozilla.com/D230859

Comment 3

[Christopher]

Looks like this may have been fixed by 20241230044734 at the latest. I'll close this as invalid

Comment 4

[Christopher]

It came back after upgrading to 136 and I had to downgrade all the way back to 20241215043337 to get it working again. I'm not sure why it was working with newer versions before, or why it broke again, so I've reopened the bug report.

Comment 5

[Martin Stránský [:stransky] (ni? me) (PTO, back on Feb 17)]

Can you use mozregression again to find the broken commit?
Thanks.

Comment 6

[Christopher]

It found https://phabricator.services.mozilla.com/D230859 again. As far as I can tell when I first boot my computer firefox (post 12-15-2024) will incorrectly detect a device pixel ratio of 1 on my monitor, but if I allow my monitors to sleep (output * dpms off through swayidle) then turn them back on (output * dpms on again only tested through swayidle), firefox will correctly detect a pixel ratio of 2 until I reboot.

Comment 7

[Martin Stránský [:stransky] (ni? me) (PTO, back on Feb 17)]

Do you see exactly the 'Window Device Pixel Ratios' 1 in about:support?

Comment 8

[Martin Stránský [:stransky] (ni? me) (PTO, back on Feb 17)]

Please run Firefox on terminal with MOZ_LOG="Widget:5" and attach the log here.
Thanks.

Comment 9

[Christopher]

Attachment: log with MOZ_LOG="Widget:5"

Yes, about:support shows "Window Device Pixel Ratios 1", and I have attached the requested log.

Comment 10

[Martin Stránský [:stransky] (ni? me) (PTO, back on Feb 17)]

Can you please run again with:

WAYLAND_DEBUG=1 MOZ_LOG="Widget:5"

and attach the log again.
Thanks.

Comment 11

[Christopher]

Attachment: firefox.log WAYLAND_DEBUG=1 and MOZ_LOG="Widget:5"

I have attachedthe requested log

Comment 12

[Martin Stránský [:stransky] (ni? me) (PTO, back on Feb 17)]

Looks like dupe of Bug 1943583.