1672993 - Linux system-wide audio crackles when scrolling/redrawing

Status: RESOLVED WONTFIX

(Core :: Widget: Gtk, defect)

Description

[Rasmus Larsen]

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:82.0) Gecko/20100101 Firefox/82.0

Steps to reproduce:

I've run a mozregression bisect that identifies the culprit as being potentially being this diff: https://phabricator.services.mozilla.com/D89188. However, this was also the first mozilla-central or autoland build that was able to start and display the window properly, so it not completely certain.

The applications that I know for sure have audio-playback issues when Firefox redraws:

Firefox
Plexamp
Spotify Client
Audacious
VLC
MPV

To reproduce in any affected version of Firefox I simply load up a video on YouTube and start scrolling up and down. The crackling happens when scrolling on any other page, but the constant motion of the video provides a good source of redrawing.

Actual results:

After updating to Firefox 82 on my Manjaro installation I started to notice crackling audio while watching videos. At first I thought it might be isolated to Firefox, but after some testing it turns out to affect system-wide audio, but only when Firefox redraws. This being both scrolling and watching videos. This does not happen when taxing the computer with highly parallel compiles, or playing graphically intensive games.

The system is a 3900x with 32 GB of RAM and a 5700XT.

Expected results:

No audio issues. As was the case for Firefox 81 and (at least) autoland build bb007859.

Comment 1

[Rasmus Larsen]

A new way to reproduce:

Find a YouTube video with a static image (to isolate out movement). I used this one https://youtu.be/zaOlvv21PZE. Move the mouse over the video so playback controls are shown. When they are shown crackling happens, but when they disappear the crackling also stops.

The above reproduction also revealed another symptom of the problem. Having an un-minimized window hidden behind the Firefox window, navigating to a dark webpage - like the video from the above, and inducing the crackling by either scrolling, doing the trick with the playback controls, or both, lets you see a ghostly image of the window behind the Firefox window. However, having an un-minimized window behind the Firefox window is not the cause of the crackling as it happens regardless.

Comment 2

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

Set release status flags based on info from the regressing bug 1662425

Comment 3

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

Do you run Firefox on Wayland backend? Because the referenced bug is Waylan specific and also I have no idea how that can be related to any audio playback.

Comment 4

[Rasmus Larsen]

I do not, which is what also is the reason for my "potentially" in the original report. I ran a mozregression bisect and the linked build is the one that it spit out. However, there were also several builds that straight up didn't run on my system. DE-wise I run completely stock Manjaro XFCE configuration.

This is the bisect log: https://i.imgur.com/7I6SAbz.png. The last few autoland builds that I set as "bad" either didn't actually produce a drawable window (by trying to create a 17000x17000 surface according to the output) or drew the screen non-interactable, enlarged roughly 300%, and stretched. If those should've been marked as "skip" instead I'm happy to do another mozregression run.

If there's anything else you can think of for me to try I'm also very eager to try and help. I've been booting into Windows for certain tasks because of this issue and I would rather not have to do that.

Lastly, I would like to point out that I didn't personally set the "regressed by" setting because I was unsure whether it was actually the offending bug - specifically because I don't use Wayland myself.

Comment 5

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

Can you try to enable/disable WebRender [1] to see if there's any difference?

[1] https://www.techrepublic.com/article/how-to-enable-firefox-webrender-for-faster-page-rendering/

Comment 6

[Rasmus Larsen]

Enabling Webrender seems to have completely fixed this problem.

Comment 7

[Ryan VanderMeulen [:RyanVM]]

Fx84 goes to RC next week with WR enabled by default from some Linux users. This seems worrying?

Comment 8

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

As WebRender fixes that it looks ok.

Comment 9

[Ryan VanderMeulen [:RyanVM]]

Whoops, I misread comment 6 :)

Comment 10

[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 11

[Gian-Carlo Pascutto [:gcp]]

It's unclear if this is really a Firefox problem or a driver problem ("it turns out to affect system-wide audio" strongly hints to a driver issue), but given that WebRender is now the default, I'm going to close this.