I installed the laptop-mode-tools to control my external harddrive. I followed closely the wiki and I managed to configure the
exactly, it is explained in the wiki.
It works (kind of) but I don't know this is the right behaviour. It powers off my external harddrive, but after a while it powers it on again even if I don't touch the external harddrive. I thought when once the harddrive powered off it remains so until I use it.
Is this the proper behavior of the laptop-mode-tools program?
These are my configuration settings (Exactly the same suggested in the wiki).
DEBUG=0 CONTROL_USB_AUTOSUSPEND=1 BATT_SUSPEND_USB=1 LM_AC_SUSPEND_USB=1 NOLM_AC_SUSPEND_USB=0 AUTOSUSPEND_TIMEOUT=2
Some DE have index services (e.g. gnome) in the background. Maybe it is one of those which wakes it up again. To check you can install something like "iotop" and have a look at the processes when the drive gets woken up.
Another avenue is that the drive itself has powermanagement options to be set additionally. You can check on them with hdparm.