Affected versions

• 85.0a1(20201214091023)

Affected platforms

• Win7x86

Steps to reproduce

1. Launch FF.
2. Notice the launch pages.

Expected result

• All of the browser window and web contents are displayed without any issues.

Actual result

• The page is displayed either with a blank white intermittence , either the whole screen going black.

Suggested Severity

• Even tough this issue was only encountered on one device, I would S3 this issue because it is still a significant UI issue that could manifest on other low-end configurations as well.

Regression range

• Manual regression range searching is required here because mozregression-ui can not be installed on this OS . Will return with one ASAP.

Notes:

• Screen cast of the issue: https://drive.google.com/file/d/1wTjiHnylbfdUxJyKF0UJyP7Jfxo6DLkW/view?usp=sharing
• This issue was encountered with fission and webrender preffs off
• This issue does not occur in RC3 84.0(20201211215739)
• This issue was not encountered on any other OS running 7x86
• This issue does not encounter on latest Chrome.
• This issue occurs for any webpage accessed.
• This may be a device specific issue seeing as how the hardware configuration on which this was encountered is as follows: 2 GB RAM, Intel GMA 500, Intel Atom

Jeff, could this be related to recent win7/DWM changes?

Vlad, can you post the about:support for that device?

Hello,

I have attached the about:support of the affected device as well.

Thanks Vlad. I can see that your firefox is running with software webrender. Could you try disabling that by ensuring that gfx.webrender.software is false and gfx.webrender.all is true in about:config, restart Firefox, and see if that helps? Thanks.

Seems likely a SW-WR issue on Intel Atom, Vlad to confirm. Probably regressed by bug 1681921.

Andrew, should we disable SW-WR by default on this platform?

Could you also try with gfx.webrender.software.d3d11 set to false, gfx.webrender.software set to true and gfx.webrender.all to set false? Thanks!

Driver might be unstable, driver version seemed to close to blocked version.

• https://searchfox.org/mozilla-central/rev/5a90b263f71b558fd14bade65b0c4ae5e216e646/widget/windows/GfxInfo.cpp#1423

(In reply to Andrew Osmond [:aosmond] from comment #6)

Could you also try with gfx.webrender.software.d3d11 set to false, gfx.webrender.software set to true and gfx.webrender.all to set false? Thanks!

Hello,

I have managed to reproduce the issue with the same repro steps as in Description with the configuration suggested in comment 6 with Nightly 86.0a1(20210105215658)

Disabling the d3d11 compositor (gfx.webrender.software.d3d11=false), while using software WR (gfx.webrender.software=true) gives me quite a few glitches, though I can't reproduce anything as bad as a fully black or white window).

Unfortunately the screen recording from comment 0 doesn't appear to load for me.

I can still repro this on latest m-c, and disabling the partial present code makes this go away.

Managed to reproduce this fully, by disabling the gpu process.

Lee's patches in bug 1686363 fix all the issues that I can find.

Vlad, can you confirm if bug 1686363 fixed the issues you were experiencing?

Hello

Confirming this issue as verified fixed and no longer present on 86.0a1(20210119091250) and 85.0(20210118153634) with the affected Win7x86 device.