Cant resume from sleep on 5.12-rcx regression?

[Malte Deiseroth]

Hey guys.

I think, maybe I found a regression in 5.12.

TLDK: Screen stays black after resume from sleep on kernel 5.12-rcx but 
not on 5.11.12


I compiler a 5.11.12 and a 5.12-rc6 Kernel on my  Ubuntu 20.10 T480 
Laptop. With the 5.11.12 kernel I can safely boot and put the laptop 
into sleep by closing its lid. Up on opening, everything works fine. 
However with the 5.12-rc6 (I also tested on rc2 and r4) I can not do 
this. After sleeping, the laptop wakes up, but the screen stays black. I 
can still ssh into the machine and it works, but I also cant open any 
ttys. I tried to gather some logs or any kind of information, but I 
don't really know what I'm searching for.

My setup might be slightly out of the ordinary, as I have an dm-crypt 
encrypted filesystem with an encrypted swap partition.

I hope I'm not wasting anyone's time here, but from what I understand 
about kernel development this should not happen.


All the best

Malte Deiseroth