i915 w/5.19: wild flickering glitching technicolor pyrotechnics on resumption from suspend

Using the i7-11850H's iGPU, when I wake my Thinkpad X1 Extreme Gen 4 from suspend on 5.19-rc1, the display shows wild flickering with strobing colors and more artifacts than real pixels in an utter disaster explosion of pantone, as though bombs were dropped on the leprechauns at the base of the rainbow. That sounds ridiculous, but the strobing pattern really is a sight to be seen.

I can only stop it by rebooting.

The system is otherwise operational and fine. Nothing in dmesg, even with i915 debugging enabled, and if it weren't for the display artifacts, I believe the actual rendering in video memory would be fine. So this sort of looks like a display driver or some sort of PSR problem.

It's pretty trivial to reproduce: I just put my laptop to sleep and wake it back up.

I found that reverting the two drm merges (with git revert -m) from 5.19-rc1 "fixed" the issue.