On my Dell Alienware 17R3 with Samsung Pro 960 NVMe SSD I had a problem suspending/resuming lockup fixed by editing
/etc/default/grub and adding the parameter
acpiphp.disable=1 to the line containing:
Afterwards it looks like this:
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpiphp.disable=1"
Save the file. Next update
/boot/grub.cfg and generate a new
initrd.img with the command:
Finally reboot and test.
I don't have the PM961, but rather the 960 Pro so haven't experienced your issue. If none of the other answers or comments help one last thing you could try is:
/etc/default/grub LINUX kernel argument list. I just found this in Arch Linux. There are other steps you may wish to investigate in the link.