Gnome Xwayland, Debian Testing, Intel HD Graphics 630 (KBL GT2)

In the past, the password popup was intermittently black for a short moment. Now it is permanently black.
It could heal its broken appearance because its text was greyed out for the first 500ms and triggered a new frame afterwards, but with bug 1650961 this regression became visible.

With security.notification_enable_delay:0 I could find the actual regressor:
WIth last good, it mostly works correctly, but in rare cases, the dialog is black, but could heal itself after a short moment.
WIth first bad, it may work correctly once, but otherwise the dialog is and stays black until it gets hovered. (GLX) The broken state is cached.
I think the broken state that is responsible for the black dialog (and now cached) may be the cause of bug 1650246 (EGL) as well.

Screencast (Ctrl+Alt+Shift+R):
last good (left): mozregression --repo autoland --launch 884fb03cc432a61def76f4d4dd6a3a6d054225ec --pref gfx.webrender.all:true security.notification_enable_delay:0 -a https://github.com/
first bad (right): mozregression --repo autoland --launch b9a02e153bcd9a462d493530cd8cd4ee830c5d90 --pref gfx.webrender.all:true security.notification_enable_delay:0 -a https://github.com/

mozregression --good 2020-07-01 --bad 20200717093907 --pref gfx.webrender.all:true -a https://github.com/

10:37.10 INFO: Last good revision: 27cbb7b4106c901018e49465d38eea9554a7e04b
10:37.10 INFO: First bad revision: 3a9cc2dab8ec9f6f332f15946f287fbcad130550
10:37.10 INFO: Pushlog:
https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=27cbb7b4106c901018e49465d38eea9554a7e04b&tochange=3a9cc2dab8ec9f6f332f15946f287fbcad130550

3a9cc2dab8ec9f6f332f15946f287fbcad130550 Zibi Braniecki — Bug 1650961 - Restrict the clickjacking delay to credit card fields. r=abr

mozregression --good 2020-07-01 --bad 2020-07-09 --pref gfx.webrender.all:true security.notification_enable_delay:0 -a https://github.com/

8:30.91 INFO: Last good revision: 884fb03cc432a61def76f4d4dd6a3a6d054225ec
8:30.91 INFO: First bad revision: b9a02e153bcd9a462d493530cd8cd4ee830c5d90
8:30.91 INFO: Pushlog:
https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=884fb03cc432a61def76f4d4dd6a3a6d054225ec&tochange=b9a02e153bcd9a462d493530cd8cd4ee830c5d90

b9a02e153bcd9a462d493530cd8cd4ee830c5d90 Nicolas Silva — Bug 1635153 - Cache the result of gdk_window_get_origin. r=masayuki

Your latest try build didn't fix this bug:
mozregression --repo try --launch c9c7e56a30ca7efad402c0901f5bb2e6451e92cc --pref gfx.webrender.all:true -a https://github.com

Basic is unaffected. OpenGL has the same behavior as WebRender.
With GPU process disabled there is a ~50% chance that it's not black.
mozregression --repo try --launch c9c7e56a30ca7efad402c0901f5bb2e6451e92cc --pref gfx.webrender.all:true layers.gpu-process.enabled:false -a https://github.com

Should be the same as bug 1652743 and hopefully fixed by it.

Fixed in bug 1652743.

Confirmed, thanks! Now it's broken like before the regression and only black for a short moment.
https://hg.mozilla.org/integration/autoland/shortlog/038c4d4d8fb0
mozregression --repo autoland --launch 038c4d4d8fb0 --pref gfx.webrender.all:true -a https://github.com