I have a ThinkPad T480 that I have been running linux on since day 1, approximately 1 year now. I also had the same problem with a previous laptop (ThinkPad T460).
In short, everything seems to suspend okay. I can close the lid, after a few moments the outside light on the lid starts pulsating, indicating suspend state.
However, when in suspend, there is what I would consider a higher than normal drain on the battery. For example, I had the laptop plugged in and suspended yesterday, and I unplugged it but kept it in suspend mode. 15-18 hours later, I opened it up again to see it had drained to 85%, so it's draining about 1%/hour.
I have TLP and powertop installed and set to defaults. I've found other people with this problem online but no solution that's been offered to them has worked for me.
Has anyone had the same problem, or knows of ways to troubleshoot?
edit: here is the contents of /proc/acpi/wakeup
Device S-state Status Sysfs node
GLAN S4 *disabled pci:0000:00:1f.6
XHC S3 *enabled pci:0000:00:14.0
XDCI S4 *disabled
HDAS S4 *disabled pci:0000:00:1f.3
RP01 S4 *disabled pci:0000:00:1c.0
PXSX S4 *disabled
RP02 S4 *disabled
PXSX S4 *disabled
RP03 S4 *disabled
PXSX S4 *disabled
RP04 S4 *disabled
PXSX S4 *disabled
RP05 S4 *disabled
PXSX S4 *disabled
RP06 S4 *disabled
PXSX S4 *disabled
PXSX S4 *disabled pci:0000:03:00.0
RP08 S4 *disabled
PXSX S4 *disabled
RP09 S4 *disabled pci:0000:00:1d.0
PXSX S4 *disabled
RP10 S4 *disabled
PXSX S4 *disabled
RP11 S4 *enabled pci:0000:00:1d.2
PXSX S4 *disabled pci:0000:3d:00.0
RP12 S4 *disabled
PXSX S4 *disabled
RP13 S4 *disabled
PXSX S4 *disabled
RP14 S4 *disabled
PXSX S4 *disabled
RP15 S4 *disabled
PXSX S4 *disabled
RP16 S4 *disabled
PXSX S4 *disabled
RP17 S4 *disabled
PXSX S4 *disabled
RP18 S4 *disabled
PXSX S4 *disabled
RP19 S4 *disabled
PXSX S4 *disabled
RP20 S4 *disabled
PXSX S4 *disabled
RP21 S4 *disabled
PXSX S4 *disabled
RP22 S4 *disabled
PXSX S4 *disabled
RP23 S4 *disabled
PXSX S4 *disabled
RP24 S4 *disabled
PXSX S4 *disabled
SLPB S3 *enabled platform:PNP0C0E:00
LID S4 *enabled platform:PNP0C0D:00
