User Agent: Mozilla/5.0 (Windows NT 10.0; rv:90.0) Gecko/20100101 Firefox/90.0

Steps to reproduce:

Use Firefox on a Samsung Galaxy Book Go with a Snapdragon 7c and Adreno 618.

Actual results:

Periodically the browser will become unresponsive for several seconds and the screen will flash. After the flash, functionality will continue normally until the next unresponsive incident.

I have determined this is a WebRender issue because on force disabling WebRender and using the Direct3D 11 path, the issue does not occur.

Expected results:

Normal browsing.

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

vinceying113, thank you for reporting. Can you attach about:support to this bug?

I attached about:support.

Thank you for the about:support.

:vinceying113, are there STRs that could reproduce the problem easily? Does the problem happen with pref gfx.webrender.compositor = false in about:config?

Them problem does not occur when WebRender is disabled. It should be able to be reproduced in general browsing. I don't think there needs to be any video playing in order to trigger the issue.