Freefall

hpfall is a simple daemon providing HDD shock protection for HP laptops supporting the feature officially called "HP Mobile Data Protection System 3D" or "HP 3D DriveGuard".

Kernel
You need to activate the following kernel option either as built-in or module.

Software
The hpfall daemon and init script can be found in :

Configuration
Set your HDD in.

Service
You can now start hpfall:

To start hpfall at boot time, add it to your boot runlevel:

Testing
After reboot with new kernel, check if hp_accel driver was initialised correctly

Testing Shock protection
Find your HDD's unload_heads file:

Go to it's directory and run:

Lift you laptop into free space and simulate the free fall while holding it firmly with your hands. About 10 cm should be enough. If the disk protection works then you should hear your HDD making "click" sound, see one of your laptop's LEDs flashing and the watch value's background should permanently turn black.