Waking up Linux from suspend mode

To see wake-up sources on Linux, use acpitool -w:

acpitool -w

   Device S-state  Status   Sysfs node
  ---------------------------------------
  1. UAR1  S3 *disabled
  2. RP01  S4 *disabled  pci:0000:00:1c.0
  3. PXSX  S4 *disabled
  4. RP02  S4 *disabled

[cut for brevity]

  16. RP08  S4 *disabled  pci:0000:00:1c.7
  17. PXSX  S4 *disabled  pci:0000:0e:00.0
  18. GLAN  S4 *enabled   pci:0000:00:19.0
  19. EHC1  S3 *enabled   pci:0000:00:1d.0
  20. EHC2  S3 *enabled   pci:0000:00:1a.0
  21. XHC  S4 *enabled   pci:0000:00:14.0
  22. HDEF  S4 *disabled  pci:0000:00:1b.0
  23. TPD4  S4 *disabled
  24. TPD7  S0 *disabled
  25. TPD8  S0 *disabled
  26. PEG0  S4 *disabled  pci:0000:00:01.0
  27. PEGP  S4 *disabled  pci:0000:01:00.0
  28. PEGA  S4 *disabled
  29. PEG1  S4 *disabled
  30. PEG2  S4 *disabled
  31. LID0  S3 *enabled   platform:PNP0C0D:00
  32. PBTN  S3 *enabled   platform:PNP0C0C:00

To modify:

 sudo acpitool -W 18

Result:

18. GLAN  S4 *disabled  pci:0000:00:19.0

Or use the raw kernel API:

cat /proc/acpi/wakeup
echo GLAN | sudo tee /proc/acpi/wakeup
cat /proc/acpi/wakeup