I installed Ubuntu 18.04 on a new ASUS Zenbook recently and virtually everything works almost perfectly. With one exception: Suspend/Resume is broken. Ubuntu seems to be aware of that and by default, selects
$ cat /sys/power/mem_sleep [s2idle] deep
Of course, this means that the laptop's battery is down by about 30% after a day of sleep and it means that the laptop really isn't useful as the mobile device it's supposed to be. I can activate deep sleep by
$ echo deep > /sys/power/mem_sleep
And then the computer does suspend properly (for example via
pm-suspend). I can see this because the power indicator LEDs on the side and in the power button start blinking slowly, in the same way as they do on my four-year-old Zenbook. If I wake the laptop up by pressing the power button briefly (or by opening the lid), the computer seems to start waking up (the power indicator LEDs go from blinking to steady light), but neither does the screen turn on, nor does the computer react to the keyboard in any way, nor can I ssh into it.
There are a couple of posts online that seem to find similar behavior with the nouveau driver for NVIDIA graphics cards. But neither does my computer have an NVIDIA card (it has a built-in Intel), nor does the nouveau driver accidentally get loaded.
Another set of online advice recommends using older/new kernels. I've tried kernel versions down to 4.14.41 and up to some 4.18 versions, both none of them changed this behavior.
I'm a little stumped here. I don't even know where to start diagnosing this. Any help would be greatly appreciated.
p.s. Hibernate doesn't work either, but I'm not overly eager to get it to work.