The Evo has BIOS support for APM and has a smart battery capable of reporting its charge highly accurately. Compaq claims that the Li-Ion batteries in the Evo are immune to the supposed "memory effect".
The Openlinux 3.1.1 kernels includes APM support like a module so you have to active the module at boot if you want it running!
From within KDE, go to the Kmenu -> Preferences -> System -> Startup ->Kernel Modules -> Others -> apm then select on the "status box" the "load on Boot" and Apply to start the daemon.
The state of the battery can be determined by examining /proc/apm.
Here is an example:
cat /proc/apm
1.15 1.2 0x03 0x01 0x00 0x01 99% -1 ?
In this case, the output, shown on the second line above, indicates that the battery charge is at 99% of capacity.)
The kernel will attempt to reduce power consumption while idle, and it also supports turning off the system completely upon a system halt.
Use the following command to shut down Linux cleanly and turn the system power off:
shutdown -h now
Standby means that the hard disk is stopped, and most components (including the CPU and screen) are powered down. Pressing a key will wake the system up immediately. Standby leaves the system lights normally lit.
I have not used "standby" by now. Whenever I would have used it I will report my results here.
Suspend is similar to standby except that more components are turned off, and the system needs an APM signal (like pressing the suspend button). Note that suspend DOES use battery power and that if the battery runs out, the system will halt entirely.
I have not used "standby" by now. Whenever I would have used it I will report my results here.
I do not know if the Evo has a particularly feature under Windows called "hibernation mode", which (if properly configured) allows you to suspend the machine entirely. (not time to read the manuals). When a notebook enters hibernation mode, it saves the contents of RAM to a DOS file in c:\, and then shuts off the disk drive. If the system is turned back on within 10 minutes, the contents of RAM are unchanged and the system can be used immediately. After 10 minutes or so, or if the battery has been changed, the contents of RAM are restored from disk, an operation that takes about 20 seconds. When it is hibernating, there will be no lights on, except maybe the battery light if the system is plugged in.
I do not know if Hibernation does work under Linux with the Evo! It works on other notebooks like the Toshiba Libretto, which uses a hidden hard disk partition.