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Bug 1824278 - Firefox not adjusting to scaling on Wayland
Summary: Firefox not adjusting to scaling on Wayland
Keywords:
Status: CLOSED NOTABUG
Alias: None
Product: Fedora
Classification: Fedora
Component: firefox
Version: 31
Hardware: x86_64
OS: Linux
unspecified
unspecified
Target Milestone: ---
Assignee: Gecko Maintainer
QA Contact: Fedora Extras Quality Assurance
URL:
Whiteboard:
Depends On:
Blocks: ffwayland
TreeView+ depends on / blocked
 
Reported: 2020-04-15 17:25 UTC by Andy
Modified: 2020-05-20 13:29 UTC (History)
12 users (show)

Fixed In Version:
Doc Type: If docs needed, set a value
Doc Text:
Clone Of:
Environment:
Last Closed: 2020-04-16 13:40:50 UTC
Type: Bug
Embargoed:

Attachments (Terms of Use)
Firefox rendered too large after reducing scaling (1.49 MB, image/png)
2020-04-15 17:25 UTC, Andy 		no flags Details
Firefox rendered too small after scaling up (686.93 KB, image/png)
2020-04-15 17:25 UTC, Andy 		no flags Details
View All

Description Andy 2020-04-15 17:25:13 UTC 
Created attachment 1679150 [details]
Firefox rendered too large after reducing scaling

Description of problem:

I have my internal screen set to 125% scaling. When I plug an external screen for which I set scaling to 100%, overall scaling is reset to 100%.

Whenever the scaling is changed by that means, Firefox's layout doesn't seem to follow. The window borders in Gnome's overwiew are correct, also mouse clicks seem to be caught correctly – but visually you only see part of the scaled-up Firefox UI, or it only takes ⅔ of the window and the rest is black.

See screenshot for a Gnome overview after setting scaling from 100% to 125% while Firefox was open.

Version-Release number of selected component (if applicable):
75.0 but I've seen the issue since upgrade to F31.


How reproducible:

Always.


Steps to Reproduce:

1. Open Firefox on Wayland.
2. Set increase screen scaling, f.e. from 100% to 125% or 200%
3. Open Gnome's overview (by pressing Super or clicking "Activities"

Actual results:

* Firefox' UI stays scaled, and is cut off.
* Inputs seem to be accepted in the right places (clicking top right somewhere will open the menu)

Expected results:

Also the UI scales after scaling changes

Additional info:
See screenshots
Comment 1 Andy 2020-04-15 17:25:51 UTC 
Created attachment 1679151 [details]
Firefox rendered too small after scaling up
Comment 2 Martin Stransky 2020-04-15 21:35:20 UTC 
Can you please try latest nightly under Wayland [1]?
Thanks.

[1] https://fedoraproject.org/wiki/How_to_debug_Firefox_problems?rd=Bug_info_Firefox#Testing_Mozilla_binaries
Comment 3 Andy 2020-04-16 13:30:35 UTC 
Hi Martin. Thanks for getting back to me.

This morning I tried using two screens with different scales, and dragging the window between the two screens is showing the issue as well.

I tried the latest nightly with Wayland backend, and everything's fine. Following that, I tried launching my installed Firefox with a clean profile, and it's fine as well.

So it must be some profile setting that is disturbing.

I remember setting some things to ensure Firefox uses hardware acceleration on my system, which might be the cause. I'll investigate.
Comment 4 Andy 2020-04-16 13:40:50 UTC 
It seems to have been the combination of

- layers.acceleration.force-enabled
- gfx.webrender.all

that caused the issue.

I changed their defaults to fix some issues which I had with WebGL.

Thanks!
Comment 5 Andy 2020-05-20 13:29:14 UTC 
Apparently another upgrade fixed it, it works now even with layers.acceleration.force-enabled active.
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