I have a Dell xps 13 (9343) on ubuntu 18.04 (kernel version 4.15.0-42-generic) with BIOS version A18. I'm having problems with suspend/resume, but only when hyperthreading is disabled in the BIOS and only when the battery power is being used.
I have performed many different tests. There was no scenario where hyperthreading was disabled and battery power was being used at any point where suspend/resume worked correctly. In other words, suspend/resume only worked correctly with hyperthreading disabled when AC power was not interrupted at any point.
With hyperthreading enabled, I found no scenario where suspend/resume failed.
Is there any hope that if the kernel behaved differently it might remedy this?