Closed Bug 1638469 Opened 10 months ago Closed 10 months ago

Disable WebRender on Windows 7 without DWM composition


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

Windows 7



Tracking Status
firefox77 --- wontfix
firefox78 --- fixed


(Reporter: aosmond, Assigned: aosmond)


(Blocks 2 open bugs)


(Keywords: correctness)


(1 file)

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


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.

Pushed by
Disable WebRender on Windows 7/8 without DWM composition enabled. r=jrmuizel
Closed: 10 months ago
Resolution: --- → FIXED
Target Milestone: --- → mozilla78
See Also: → 1638285

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

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

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!

Flags: needinfo?(jbonisteel)
Flags: needinfo?(aosmond)

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

Flags: needinfo?(jbonisteel) → needinfo?(pascalc)

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

Flags: needinfo?(aosmond)

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

Good news then, thanks!

Flags: needinfo?(pascalc)
Blocks: 1637497
No longer depends on: 1637497
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