There are several Experimental Options you can turn on when you
configure the kernel with kernel configuration file.
Reopen internal serial port on power resume. Default is off.
If you turn on this option, the internal serial port opened before
suspend is reopened on resume.
NOTE: This option only work with internal serial port.
Extra power saving on some machines. Currently known to work with IBM
ThinkPad230. YOU MUST NOT TURN ON THIS OPTION IF YOU ARE NOT USING
THINKPAD.