1795557 - Scrolling stuttering / lagging / choppy with laptop trackpad

Status: UNCONFIRMED

(Core :: Graphics: WebRender, defect)

Description

[klabsmaster]

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:105.0) Gecko/20100101 Firefox/105.0

Steps to reproduce:

I'm scrolling using two fingers on my laptop trackpad

Actual results:

Scrolling is laggy, but if i use the touch screen to scroll on the same web page it's very smooth, no stuttering or frame drops.

Expected results:

Scrolling should be smooth and not stutter/lag when using two fingers on trackpad.

Tried disabling all extensions, creating new Mozilla folder in Appdata (new profile) and also installing Nightly but nothing helped at all.

Comment 1

[klabsmaster]

Should add that i'm using a fully updated Windows 11 22H2 on a Surface Laptop 3.

Comment 2

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

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

Comment 3

[Emilio Cobos Álvarez [:emilio]]

Could you take a performance profile like https://firefox-source-docs.mozilla.org/performance/reporting_a_performance_problem.html? Is it just slow or jumpy?

Given it's smooth with the touch screen it probably means that it's an issue on the widget side of things, but a profile would still be useful either way.

Comment 4

[klabsmaster]

That's weird and funny but when i record using the tool, it doesn't lag anymore, here is the link anyways: https://share.firefox.dev/3VzZvxu

Yes it's slow, lots of stuttering.

I recorded a video with OBS (which records very smooth videos so you will be able to see easily) https://dl.dropboxusercontent.com/s/v6xpedsrx88z65c/2022-10-16%2021-31-59.mkv

From the beginning i use two fingers with the trackpad to scroll, it's stuttering, from 00:18 i use my finger to scroll with the touch screen, you can see it's very smooth.

Comment 5

[Timothy Nikkel (:tnikkel)]

Kind of looks like your trackpad driver might be sending us discrete pan events?

The problem doesn't happen in other web browsers I take it?

Comment 6

[klabsmaster]

Yes, scrolling is indeed smooth in Microsoft Edge

Comment 7

[Timothy Nikkel (:tnikkel)]

Thanks for confirming. What happens if you change the pref apz.windows.force_disable_direct_manipulation to true in about:config? Any difference?

What happens if you use another method of scrolling, ie the keyboard (arrows keys or space bar), a mouse wheel if you have one, or clicking on the scrollbar arrows or dragging the scroll thumb or clicking the in scroll track?

Comment 8

[klabsmaster]

Mouse wheel: smooth
Keyboard arrows: smooth
Scrollbar arrows: smooth
Autoscroll (clicking on mouse wheel): smooth
(tested before enabling the flag)

With apz.windows.force_disable_direct_manipulation set to true after restarting, it seems to be smooth but it's hard to tell because the movements are very fast.

Comment 9

[Timothy Nikkel (:tnikkel)]

Thanks for testing.

And this happens on any webpage, even simple ones? I ask because the amazon page in the video has scroll event listeners and a wheel event listener which can affect this type of thing.

Comment 10

[klabsmaster]

Yes, even in Firefox pages such as extensions list, i just thought it was a little bit more severe on amazon

Comment 11

[klabsmaster]

Anything else could be done to mitigate the issue in the meanwhile ? "apz.windows.force_disable_direct_manipulation" removes the ability to go back to the previous page with gestures for me.