https://bugzilla.kernel.org/show_bug.cgi?id=207383
--- Comment #41 from Duncan (1i5t5.duncan@cox.net) --- (In reply to Alex Deucher from comment #40)
Does this patch help?
Booted to v5.7 with it applied now. We'll see. Since the bug can take awhile to trigger on my hardware, if the patch fixes it I won't know for days, and won't be /sure/ for say a week, the reason bisecting was taking so long.
(It wouldn't apply to current 5.8-rc4-plus-an-s390-pull. Too tired to figure out why ATM but if it's because it was there already, hopefully it was pulled in after v5.8-rc3 as I tested that and got the same graphics freeze with the characteristic trace, so if the patch was already in v5.8-rc3, it does /not/ fix the bug.)
As for bisecting, I've hard-crashed twice on the current step, apparently with a different bug, so while _this_ bug hasn't seemed to trigger yet, I haven't gotten the necessary confidence that it's a bisect-good. So hopefully this patch /does/ fix it, and I can put this entirely too frustrating bug-bisect behind me!