1624921 - [WAYLAND][GNOME 3.36] Nightly often freezes for a few seconds when switching from other Window

Status: RESOLVED FIXED

(Core :: Widget: Gtk, defect, P2)

Description

[Marko]

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:76.0) Gecko/20100101 Firefox/76.0

Steps to reproduce:

Hardware: Intel i5 6600, 16GB DDR4, AMD RX 5700XT
Software: Fedora 32 Beta, gnome-shell 3.36.0, mutter 3.36.0, Wayland backend

Open Firefox and a few tabs, have a few other things open in the shell. Keep switching from other windows (for example nautilus) to Firefox.

Actual results:

70% of times when I switch focus to Firefox windows scrolling and the entire firefox UI freezes. After a few moments it begins working and does all the things that I've pressed when it was frozen.

Expected results:

When focusing Firefox window it should immidiately start being responsive without freezing.

Comment 1

[Marko]

Link to a video description of the bug:
https://imgur.com/a/Gp0IbQW

Comment 2

[Martin Stránský [:stransky] (ni? me)]

Do you see that with default Firefox 74 builds too? Or do you test latest nightly?
Thanks.

Comment 3

[Marko]

(In reply to Martin Stránský [:stransky] from comment #2)

Do you see that with default Firefox 74 builds too? Or do you test latest nightly?
Thanks.

Hi Martin! This issue is not present on stable 74 version, it got introduced in one of the latest nightlies!

Comment 4

[Martin Stránský [:stransky] (ni? me)]

I see.
Can you please try mozregression tool (https://mozilla.github.io/mozregression/ - you need to use a comandline version) to find a regression range?
Thanks.

Comment 5

[Marko]

IDK how to use that tool, but here is some bisecting for you :) from 2020-03-12-21-53-13 all the builds have that bug.

2020-03-11-16-39-42-mozilla-central/ GOOD
2020-03-12-09-33-12-mozilla-central/GOOD
2020-03-12-21-53-13-mozilla-central/ BAD

Comment 6

[Marko]

• Also this bug only seems to affect the full-screen mode, not windowed mode!

Comment 7

[Martin Stránský [:stransky] (ni? me)]

I see. Can you try to set widget.wayland.use-opaque-region to false and retest?
Thanks.

Comment 8

[Marko]

(In reply to Martin Stránský [:stransky] from comment #7)

I see. Can you try to set widget.wayland.use-opaque-region to false and retest?
Thanks.

Sure. Just tested it, still present with it disabled!

Comment 9

[Martin Stránský [:stransky] (ni? me)]

The mozregression range may be very useful as I don't see anything special in 2020-03-12 commits.
Please give it a try, it's super easy. If you are on Fedora, you just need:

$pip install --user mozregression
$mozregression --good=2020-03-11 --bad=2020-03-13

then the tool will launch firefox nightly from the given range and ask you if the build is good or bad and may give you exact bug number or some shrank bug range.

Thanks.

Comment 10

[Marko]

(In reply to Martin Stránský [:stransky] from comment #9)

The mozregression range may be very useful as I don't see anything special in 2020-03-12 commits.
Please give it a try, it's super easy. If you are on Fedora, you just need:

$pip install --user mozregression
$mozregression --good=2020-03-11 --bad=2020-03-13

then the tool will launch firefox nightly from the given range and ask you if the build is good or bad and may give you exact bug number or some shrank bug range.

Thanks.

Here is the output:
https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=57f9a3f2c4069bef8166df880d0b4ad8c0e92c45&tochange=0a6d64975cfa90788adf7851053f48ef523babb7

Comment 11

[Martin Stránský [:stransky] (ni? me)]

Thanks. The Bug 1617115 mentioned here affects X11 backend only, not Wayland.
Are you sure you run nighly with Wayland backend enabled, i.e. with MOZ_ENABLE_WAYLAND=1 on command line?
You can also verify that on about:support page where wayland is mentioned.

Comment 12

[Marko]

(In reply to Martin Stránský [:stransky] from comment #11)

Thanks. The Bug 1617115 mentioned here affects X11 backend only, not Wayland.
Are you sure you run nighly with Wayland backend enabled, i.e. with MOZ_ENABLE_WAYLAND=1 on command line?
You can also verify that on about:support page where wayland is mentioned.

Ohh sry, my mistake, it was set to MOZ_WAYLAND_ENABLE=1 instead of MOZ_ENABLE_WAYLAND=1!

Should I check if this occurs on X11 backend so we can just rename the issue, or should we close the issue?

Comment 13

[Martin Stránský [:stransky] (ni? me)]

(In reply to Marko from comment #12)

Should I check if this occurs on X11 backend so we can just rename the issue, or should we close the issue?

Yes, please check if that's X11 issue only. I'd need to revert the change at Bug 1617115 then.
Thanks!

Comment 14

[Marko]

(In reply to Martin Stránský [:stransky] from comment #13)

(In reply to Marko from comment #12)

Should I check if this occurs on X11 backend so we can just rename the issue, or should we close the issue?

Yes, please check if that's X11 issue only. I'd need to revert the change at Bug 1617115 then.
Thanks!

Hm it only appears to happen when running it through XWayland, on Xorg it is ok, so I guess it's not a dealbreaker, unless someone is still running Firefox under XWayland.

Comment 15

[Martin Stránský [:stransky] (ni? me)]

I think we should fix that anyway...I'll look at it.
Thanks for testing!

Comment 16

[Martin Stránský [:stransky] (ni? me)]

Attachment: Bug 1624921 [Linux/X11] Use CSD for PIP windows only, r?jhorak

Comment 17

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/f733f4c24b29
[Linux/X11] Use CSD for PIP windows only, r=jhorak

Comment 18

[Noemi Erli[:noemi_erli]]

https://hg.mozilla.org/mozilla-central/rev/f733f4c24b29

Comment 19

[antistress]

"unless someone is still running Firefox under XWayland"
I guess we're quite a few doing that (Debian Sid GNOME-Wayland here ; no Firefox-wayland available throug the repos)
Thanks for the fix