Laptop killer bug

to neko iskljucivanje tog 'park unpark' sta li?

The script that’s executed when you plug or unplug your laptop is /etc/acpi/power.sh. The relevant sections are:

function laptop_mode_enable {
...
$HDPARM -S $SPINDOWN_TIME /dev/$drive 2>/dev/null
$HDPARM -B 1 /dev/$drive 2>/dev/null
}

That is, when the laptop_mode_enable function is called, we set the drive power parameters. Now, by default laptop_mode_enable isn’t called:

if [ x$ENABLE_LAPTOP_MODE = xtrue ]; then
(sleep 5 && laptop_mode_enable)&
fi

because ENABLE_LAPTOP_MODE is false in the default install (check /etc/default/acpi-support). This means that, by default, we do not alter the hard drive power settings. In other words, the APM settings that your drive is using in Ubuntu are the ones that your BIOS programmed into it when the computer started. This is supported by the fact that people see this issue after resuming from suspend. We don’t touch the hard drive settings at that point, so the only way it can occur is if your BIOS or drive default to this behaviour.

If you enable laptop mode, then we will enable aggressive power management on the drive and that may lead to some reduction in hard drive lifespan. That’s a fairly inevitable consequence of laptop mode, since it only makes sense if the laptop enages in aggressive power management. But, as I said, that’s not the default behaviour of Ubuntu.

There’s certainly an argument that we should work around BIOSes, but in general our assumption has been that your hardware manufacturer has a better idea what your computer is capable of than we do. If a laptop manufacturer configures your drive to save power at the cost of life expectancy, then that’s probably something you should ask your laptop manufacturer about.

The following things might instead cause aggressive power management settings :

* your (laptop) harddrive firmware might have aggressive power management defaults (operating system independent)
* your (laptop) BIOS might set your harddrive to use aggressive power management (operating system independent)
* you might have enabled laptop-mode in /etc/default/acpi-support (disabled by default) which will set your harddrive to use aggressive power management

These aggressive power management settings are set by your BIOS or harddrive firmware. Windows and/or Mac OS X might be overriding these settings which might make Ubuntu look bad if Ubuntu doesn’t override these settings.