1610287 - WebRender cannot be manually disabled after navigating to specific sites using Pixel 2XL

Status: RESOLVED INVALID

(Core :: Graphics: WebRender, defect)

Description

[Valentina Virlics [:vvalentina], Ecosystem QA]

[Affected versions]:
Firefox Preview 74.0a1 Build ID 20200115093807;

[Affected Platforms]:
Android 8.0.0 (Google Pixel 2 XL);
Android 10.0.0 (Google Pixel 3);

[Steps to reproduce]:

1. Open a fresh installed Firefox Preview Nightly app on your Google Pixel 2XL device.
2. Go to about:support and observe that Graphics - compositing lists "WebRender".
3. Navigate to "http://www.agame.com/" and play a game.
4. Go to about:config and manually disable WebRender by setting the "gfx.webrender.force-disabled" pref to "true".
5. Restart the Firefox Preview Nightly app.
6. Go to about:support and observe that Graphics - Compositor section.

[Expected result]:
"Open GL" is listed under Graphics - compositing section.

[Actual result]:
"WebRender" is still listed under Graphics - compositing section.

[Notes]:

• Issue is not reproducible on Pixel 2 (Android 9).
• Issue is reproducible on Pixel 3 (Android 10).
• Issue is only reproduced for specific sites.

Comment 1

[Jessie [:jbonisteel] pls NI]

Hey Jamie, can you see if you can reproduce this?

Comment 2

[Jamie Nicol [:jnicol]]

This does not reproduce for me on a Pixel 2 (non-XL). After restarting Firefox Preview Nightly I see "OpenGL" under "compositing".

I don't have a Pixel 2XL or Pixel 3 to test on but this seems very strange to me, as the code to enable/disable webrender should be the same.

Valentina, what is the relevance of going to www.agame.com? Does it disable webrender if you don't do that step? Perhaps that website prevents the browser from being restarted properly, so the about:config change is not picked up?

Comment 3

[Valentina Virlics [:vvalentina], Ecosystem QA]

Yes, WebRender is disabled if step 3 - Navigate to "http://www.agame.com/" and play a game. - is not made.
The pref is CHANGED in about:config, the problem is that the changes don't reflect in about:support.

Comment 4

[Jamie Nicol [:jnicol]]

Interesting, thanks. And how do you restart the app after changing the pref? If you restart your phone does that make a difference?

Comment 5

[Valentina Virlics [:vvalentina], Ecosystem QA]

Just tried with device restart and works as expected: after manually disabling WebRender from about:config and restarting the phone, "Open GL" is listed under Graphics.

Comment 6

[Jamie Nicol [:jnicol]]

Okay, I guess then that something on that webpage keeps the app alive when you tried to restart, meaning that the about:config wasn’t applied.

Comment 7

[Kris Taeleman (:ktaeleman)]

Tried to reproduce this and it looks like Jamie is right. In my first try, closing the app and reopening immediately resumed the game. After force closing the app it worked as expected and I wasn't able to reproduce it again.