1491798 - A tab which is moved out of the window and back becomes empty for an unusual long moment

Status: VERIFIED FIXED

(Core :: Graphics: WebRender, defect, P2)

Description

[Darkspirit]

Attachment: 2018-09-17 14-18-32.mp4

Win10, GTX 1060

mozregression --launch 2018-09-16 --pref gfx.webrender.all:true -a about:newtab -a https://html.spec.whatwg.org/

A regression date would have to be before 2018-01-15 which has already been bad.

It can be fixed by unfocusing the window (clicking on the desktop background).
I wasn't able to reproduce this bug with gfx.webrender.force-disabled:true.

Sometimes it's also reproducible with https://www.amazon.com/, but it stays blank only for a short moment.

Comment 1

[Sotaro Ikeda [:sotaro]]

I take a look.

Comment 2

[Sotaro Ikeda [:sotaro]]

The problem might happens since we removed layers during using webrender.

Comment 3

[Darkspirit]

about:newtab can also be that bad.

Comment 4

[Darkspirit]

Attachment: 2018-09-26 21-59-54.mp4

https://www.youtube.com/watch?v=Scxs7L0vhZ4
From my perception this can happen too easily. It isn't slowness. I just need to unfocus the window or interact with website content, e.g. by hovering or clicking, to make it visible again.

Comment 5

[Maire Reavy [:mreavy]]

Hi Sotaro -- Would it make sense for me to re-assign this to someone else?  You have a lot of bugs on your plate.  Thanks!

Comment 6

[Sotaro Ikeda [:sotaro]]

I have a possible fix patch. It address the problem for me. I am going to progress the bug. Thanks!

Comment 7

[Sotaro Ikeda [:sotaro]]

Without WebRender, ClientLayerManager can use same layer resources during Tab move between windows. But with WebRender, WebRenderLayerManager cannot retain WebRender resources in during Tab move between windows.

When Tab is moved between windows, WebRenderLayerManager frees all WebRender related resources in WebRenderBridgeChild::RecvWrUpdated(). Then child side needs to trigger repaints to trigger WebRenderLayerManager transaction.

Comment 8

[Sotaro Ikeda [:sotaro]]

Attachment: patch - Schedule repaint if WebRender is updated by tab move

Comment 9

[Sotaro Ikeda [:sotaro]]

https://treeherder.mozilla.org/#/jobs?repo=try&revision=b8e3ae18d13b71ab08e5a18db89708e755a752d7

Comment 10

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/94a87c720eee
Schedule repaint if WebRender is updated by tab move r=mattwoodrow

Comment 11

[Noemi Erli[:noemi_erli]]

https://hg.mozilla.org/mozilla-central/rev/94a87c720eee

Comment 12

[Darkspirit]

Verified fixed. Thank you!