Technical Note: Sleep Issue on Dell XPS 9370 with Ubuntu 18.04 (Bionic Beaver)
I notice than when I close my lit of Dell XPS 9370, which is installed Ubuntu Linux 18.04 (Bionic Beaver),the OS does not get into deep sleep mode. It does turn off the display, and hard disk and CPU seems to get into low power mode. However, the OS consumes battery power as normal mode and if I forget to put my computer into my backpack in this sleep mode, the CPU rallies producing heats. This definitely reduce the life of my laptop and I know that I need to do something. At first, I thought this issue relates to driver due to new hardware, but after a quick Google, I found out that Arch Linux user and Bionic Beaver users see the same issue. I think the answer made by monty47 is so complete that I need no further explanation. I copied his solution here including several references for my personal educational purposes. 1. Root cause and Solution Linux Kernel supports 4 system sleep states, though some states depend on platform support codes. Those 4 states are represented by st