1782133 - Firefox Nightly 105.0a1 on Wayland often flickered or was solid black when starting

Status: RESOLVED FIXED

(Core :: Widget: Gtk, defect)

Description

[Matt Fagnani]

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:105.0) Gecko/20100101 Firefox/105.0

Steps to reproduce:

I started Firefox Nightly 105.0a1 (2022-07-26) build id 20220726214438 to 105.0a1 (2022-07-28) on Wayland with WebRender compositing in Plasma 5.25.3 on Wayland in a Fedora 36 KDE Plasma installation.

Actual results:

Firefox Nightly 105.0a1 (2022-07-26) build id 20220726214438 to 105.0a1 (2022-07-28) on Wayland often flickered between black and white or was solid black for about a second when starting. This flickering or solid black window happened most of the times I've started 105.0a1 (2022-07-26) build id 20220726214438 to 105.0a1 (2022-07-28).
This problem happened with a blank Start page as I have set in my profile and with a custom Start page. The flickering or solid black window was before the UI was shown.
105.0a1 (2022-07-26) build id 20220726214438 and earlier were flickering about 10% of the time when starting as I reported at https://bugzilla.mozilla.org/show_bug.cgi?id=1756283

I ran mozregression --good 2022-07-25 --bad 20220726214438 --persist /tmp/mozregression/persist -p ~/.mozilla/firefox/z8d4nvrc.default-nightly --profile-persistence reuse

The bisection ended with the following.

34:48.36 INFO: Narrowed integration regression window from [4f1394bc, cd97145a] (3 builds) to [2cbab5d7, cd97145a] (2 builds) (~1 steps left)
34:48.36 INFO: No more integration revisions, bisection finished.
34:48.36 INFO: Last good revision: 2cbab5d7e2a99011a19f9c9cc3c3724ccd755f5d
34:48.36 INFO: First bad revision: cd97145a6a9300aa2fb99b7cdc433042c9113025
34:48.36 INFO: Pushlog:
https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=2cbab5d7e2a99011a19f9c9cc3c3724ccd755f5d&tochange=cd97145a6a9300aa2fb99b7cdc433042c9113025

The pushlog of the first bad revisions had commits from two bugs. Bug 1777664 is more likely to be involved as it had 12 Wayland/Linux commits.

Expected results:

Firefox Nightly would start normally without flickering between black and white or solid black windows.

Comment 1

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

Set release status flags based on info from the regressing bug 1777664

Comment 2

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

:stransky, since you are the author of the regressor, bug 1777664, could you take a look?
For more information, please visit auto_nag documentation.

Comment 3

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

Emilio, I think you did some fixes for that, can you help me here please? Do we do some early painting to the window to clear background or so?
Thanks.

Comment 4

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

Hm, the Bug 1777664 may make it more visible but I can reproduce it without it too. It's clearly visible on debug builds.

Comment 5

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

The bug has a release status flag that shows some version of Firefox is affected, thus it will be considered confirmed.

Comment 6

[Emilio Cobos Álvarez (:emilio)]

Does only the content area flicker? Or also the browser UI? I don't seem to be able to repro locally, but I'm using an optimized-debug build to try so maybe it's that.

I see a 'flicker', going from a lighter dark to a darker-dark, is that what you're talking about? If so that's a bit expected since the color we're using to clear comes from the widget, and the default dark background for websites might be different if not using system colors. Should be addressable tho, I think, might need to make this a bit smarter.

A screencast would be great if possible.

Comment 7

[Matt Fagnani]

The whole Firefox window flickers between black and white or is solid black for about a second except for the title bar which has Firefox Nightly about 90% of the time. There's only black and white shown, not a lighter and darker dark. I'll see if I can figure out how to make a screencast. Is there a screencast program that would be recommended for this purpose? Thanks.

While bisecting I retried five times at each step and marked the build as bad if there was flickering or solid black 3 or more times out of 5. This problem didn't appear when I ran 105.0a1 (2022-07-28) on XWayland with MOZ_ENABLE_WAYLAND=0 ~/programs/firefox/firefox 10 times in Plasma on Wayland or when I ran 105.0a1 (2022-07-28) on Wayland 10 times in GNOME 42.3 on Wayland in Fedora 36. So the problem might be specific to Firefox on Wayland in Plasma on Wayland.

Comment 8

[Matt Fagnani]

Attachment: Screen recording of Firefox Nightly 105.0a1 (2022-7-29) flickering while starting

I'm attaching a screen recording made with OBS of Firefox Nightly 105.0a1 (2022-7-29) on Wayland flickering while starting in Plasma 5.25.3 on Wayland in a Fedora 36 KDE Plasma installation. Firefox actually flickered more times on the screen than is shown in the recording. When I made several of other similar recordings with Firefox flickering, the Firefox window only appeared to be solid black in the recording. The flickering of the Plasma desktop in the recording was not visible on the screen, and I guess it was an artifact of the recording process.

Comment 9

[Matt Fagnani]

105.0a1 (2022-7-29) build id 20220729213628 on Wayland in Plasma has had a much lower frequency of this problem with about a solid black screen about 10-20% of the time and I haven't seen flickering with it. I ran mozregression --good 20220729213628 --bad 2022-07-28 --find-fix --persist /tmp/mozregression/persist -p ~/.mozilla/firefox/z8d4nvrc.default-nightly --profile-persistence reuse

While bisecting I retried five times at each step and marked the build as bad if there was flickering or solid black 3 or more times out of 5.

17:33.20 INFO: Narrowed integration fix window from [7617aa56, 9648a34c] (3 builds) to [78a0b6b0, 9648a34c] (2 builds) (~1 steps left)
17:33.20 INFO: No more integration revisions, bisection finished.
17:33.20 INFO: First good revision: 9648a34ca72f2cf7dc1115b2b8f957e58280bf26
17:33.20 INFO: Last bad revision: 78a0b6b0e8420c82792c9911d24696f2ec5b74ea
17:33.20 INFO: Pushlog:
https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=78a0b6b0e8420c82792c9911d24696f2ec5b74ea&tochange=9648a34ca72f2cf7dc1115b2b8f957e58280bf26

The bisection ended with two changes in the pushlog for Bug 1782049 which was marked as regressed by bug 1777664 also.

9648a34ca72f2cf7dc1115b2b8f957e58280bf26 stransky — Bug 1782049 [Linux] Update nsWindow compositor configuration r=emilio
3c2b9d0429b9584cec2873730a51fe54eba906af stransky — Bug 1782049 [Wayland] Print wayland mozcontainer logs as widget one r=emilio

The fix for Bug 1782049 might have decreased the frequency of this problem back to that before 105.0a1 (2022-07-26) build id 20220726214438

Comment 10

[Ryan VanderMeulen [:RyanVM]]

Hi Matt, going off your last comment, it seems like we can close this bug out now?

Comment 11

[Matt Fagnani]

(In reply to Ryan VanderMeulen [:RyanVM] from comment #10)

Hi Matt, going off your last comment, it seems like we can close this bug out now?

The same problem still happened about 10-20% of the times when starting up to and including Firefox (and Thunderbird) 105.a1 (2022-8-16) with the solid black window being more frequent than the flickering black and white. The frequency was down from about 90% between Firefox 105.0a1 (2022-07-26) build id 20220726214438 and 105.0a1 (2022-7-29) build id 20220729213628. So this bug can be closed, but bug 1756283 could be left open.

Comment 12

[Ryan VanderMeulen [:RyanVM]]

Thanks, sounds like we can indeed use bug 1756283 to track the remaining pre-existing issue since this particular spike was addressed by bug 1782049.