Ubuntu
acpi-support package

  1. Bug #59695
  2. Comment #86

Comment 86 for bug 59695

Revision history for this message
Kamil Páral (kamil.paral) wrote : Re: default value in power.sh potentially kills laptop disks

You all talk about "insane" settings. They not such bad. The hardware manufacturers know what they are doing. If laptop harddisk go to "sleep" after 30sec of inactivity, there is a reason for that (security, power consumption). And it is perfectly ok. The problem is, the disk is not supposed to be waken up immediately.

Info #1: Today I have witnessed very similar behaviour on two different notebooks running Windows XP. That means, it doesn't have to be true that windows somehow "correct" these settings. It behaved quite same, after 20-30sec of hdd inactivity, the hdd went to sleep. The difference was, under Ubuntu it wakes immediately. Under windows, it was sleeping for several minutes, until some disk activity was needed (some system service or user intervention). *This* is how it is supposed to behave and how hdd manufacturers expect it to be, I presume.

Info #2: Laptop-mode is not enabled by default nor any settings are applied to the disk (as Matthew Garrett said before). So do not blame it. As a matter of fact, my notebook behaves correctly with laptop-mode enabled. It is putting disk to sleep only on battery and it is not waking it up immediately. It is working right like in Windows(!). According to acpi configuration file, laptop-mode is not enabled due to odd hangs on some machines.

What does it all mean? If your harddisk goes to sleep 10 times an hour, always for a few minutes, it's perfectly ok, do the math. That's how the manufacturers supposed it to be. Therefore Ubuntu should not tweak harddisk default settings. Instead, it should detect these "aggressive apm enabled" harddisks (or simply all laptops) and delay flushing intervals and slow down daemons accessing the disk. That's what the laptop-mode does. But it has some hardware compatibility issues. Ok, so let's take only a hardware-independent and non-problematic subset of laptop-mode and enable it on notebooks. It will help their disks a lot.

Simply: Do not touch the disk if you don't have to, Ubuntu. At least on notebooks. That's all.