That can happen after a few seconds like many people have described, or after a few minutes or hours. The display remains turned off, only when I press keyboard or move the mouse it gets turned on.
What can be the reason?
I'm using a bluetooth mouse, maybe it gets connected to it when it's asleep because I put them in a bag close to each other? However, I think even if it is, it's not the only reason.'
$ cat /proc/acpi/wakeup Device S-state Status Sysfs node LID S3 *enabled platform:PNP0C0D:00 IGBE S4 *enabled pci:0000:00:19.0 EXP3 S4 *disabled pci:0000:00:1c.2 XHCI S3 *enabled pci:0000:00:14.0 EHC1 S3 *enabled pci:0000:00:1d.0
What should I disable to allow waking up only by pressing a key on the keyboard?