So far ASPM is disabled in the r8169 driver due to issues on several chip version / BIOS version combinations. Commit ad46fe1c7336 ("PCI/ASPM: Add sysfs attributes for controlling ASPM link states") adds the option to enable ASPM states for a device via sysfs (provided that BIOS allows the OS to control ASPM). This commit is included in latest linux-next and may be useful for notebook users to benefit from ASPM power saving.
Heiner