1638469 - Disable WebRender on Windows 7 without DWM composition

Status: RESOLVED FIXED

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

Description

[Andrew Osmond [:aosmond] (he/him)]

+++ This bug was initially created as a clone of Bug #1637497 +++

Reported: https://www.reddit.com/r/firefox/comments/ghkj22/terrible_graphical_glitches_on_nightly/

Since a few days ago, I've been having a lot of tearing-like glitches on Firefox Nightly. They happen almost every time I:
Alt-Tab into Firefox (or switch to a Nightly window using the taskbar, or minimize it by clicking on a maximized browser window)
Switch between two Firefox windows
Close a file selection or other explorer dialog (less often)

It does not happen when switch to a different tab, in fact that is - along with moving the mouse in the general area where the bug is happening - a way to make the "ghost" image disappear. Usually it's the bottom half of the screen that doesn't "refresh".

Disabling WR resolves the issue.

--

We should disable WebRender on Windows 7 if we don't have DWM composition for the moment due to the above bug.

Comment 1

[Andrew Osmond [:aosmond] (he/him)]

Attachment: Bug 1638469 - Disable WebRender on Windows 7/8 without DWM composition enabled.

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/8184dcb24e61
Disable WebRender on Windows 7/8 without DWM composition enabled. r=jrmuizel

Comment 3

[Narcis Beleuzu [:NarcisB]]

https://hg.mozilla.org/mozilla-central/rev/8184dcb24e61

Comment 4

[Darkspirit]

Please backout and require DWM for partial present. Then it should be fine.

Comment 5

[Florian Quèze [:florian]]

Given bug 1638285 was on Firefox 77, is there something we need to uplift?

Comment 6

[Pascal Chevrel:pascalc]

Jessie, Andrew, is that big enough of a problem to be in our RC build? If it is, I'd prefer to take the uplift now to mozilla-release and not have to do a RC2 later this week. Thanks!

Comment 7

[Jessie [:jbonisteel] pls NI]

WebRender for Win7 isn't riding to release, so this doesn't need to go to RC

Comment 8

[Andrew Osmond [:aosmond] (he/him)]

We don't need to uplift as we explicitly block Windows 7, 8 and 8.1 on mozilla-beta already:

https://searchfox.org/mozilla-beta/rev/ebf7d1a20e598054d1973bdd579fa0405831be1d/widget/windows/GfxInfo.cpp#1735

Comment 9

[Darkspirit]

In bug 1638285 the user manually force-enabled WebRender by setting gfx.webrender.all to true.

Comment 10

[Pascal Chevrel:pascalc]

Good news then, thanks!