[Tracking Requested - why for this release]:

This is a regression in 73 Nightly (build 2019-12-10) from the fix for Adreno bug 1598380.

With gfx.webrender.all enabled on macOS, I see random letters missing from both web content and chrome UI text. See the attached screenshot.

I bisected this regression to this pushlog:

https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=05327537443557099272b63ade89fe36f0ad05e1&tochange=3f9482614123972f6fcd8b6a1d99dc8db8cb6c07

I don't see this problem on my Windows laptop.

Thanks for the report! This doesn't look good. I'd expect it not to affect windows, as it does not use PBOs. But the fact I cannot reproduce on Linux, Android, or my 2013 13" MBP, leads me to believe this is a driver bug of sorts :(.

Does this happen on all sites? Does it happen immediately, or after scrolling around a little?

Would you be able to set gfx.webrender.debug.texture-cache=true, restart, and take a screenshot as soon as it reproduces?

Thanks!

There are 3 other bugs filed within the past few hours for what looks like this same issue: bug 1603033 bug 1603018 bug 1602981
So this is probably pretty widespread.

This appears to affect AMD macbooks with Catalina only (though that's probably the most common configuration!). I have gotten my hands on one of those so can now investigate further.

(In reply to Jamie Nicol [:jnicol] from comment #3)

Does this happen on all sites? Does it happen immediately, or after scrolling around a little?

This happens immediately on all sites and even chrome UI text (like about:newtab and the bookmarks toolbar).

Would you be able to set gfx.webrender.debug.texture-cache=true, restart, and take a screenshot as soon as it reproduces?

(In reply to Jamie Nicol [:jnicol] from comment #8)

This appears to affect AMD macbooks with Catalina only (though that's probably the most common configuration!). I have gotten my hands on one of those so can now investigate further.

Since you now have an AMD ok to test, I assume you don't need me to test gfx.webrender.debug.texture-cache=true on my MBP. Let me know if you still would like me to test.

Yep, no need. Thanks!

(In reply to Jamie Nicol [:jnicol] from comment #8)

This appears to affect AMD macbooks with Catalina only (though that's probably the most common configuration!). I have gotten my hands on one of those so can now investigate further.

I forgot to add that, sorry (in my duped-to-here) - iMac 21.5” Retina (2017) which is essential a MacBook glued to the back of a screen, and does have AMD.

This was fixed by backing out bug 1598380

Dropping the qe+ since we cannot reproduce the issue with our devices.