Comment 233 for bug 59695

ubuntu_demon wrote:
> Since it's currently impossible to recommend to turn laptop_mode on by default I'm currently recommending this to people who are heavily affected :
> * use apm 128 while on battery (most head parks, best protection from bumps, lower power usage)
> * use apm 254 while on AC (no protection from bumps,no head parks,best performance,increased heat)
>
> The biggest reason to do so would be to protect the harddisk from bumps.
> Even if the laptop is used on battery everyday for four hours the
> Load_Cycle_Count would have to increase with 137 per hour to be able to
> reach 600.000 within three years of usage. Most people don't see their
> Load_Cycle_Count increase that fast (although some might). Most people
> don't use their laptop for four hours on battery each day. Those people
> who are afraid they will still reach the maximum Load_Count as specified
> by their manufacturer within three years of usage do need to tweak the
> "apm number while on battery".

OK, I see how the math stacks up, and I agree. In that case the shock
protection probably outweighs the HD wear from the parking, even when
laptop mode is not enabled.

> This won't interfere with people who are using laptop-mode since laptop-
> mode doesn't touch apm but only spindown.

Not by default, but be aware that it _can_ be configured to configure
APM as well. That's why, in the acpi-support solution for Debian, I
added a check that laptop-mode.conf is configured to not touch APM. If
laptop-mode.conf is configured to do APM, acpi-support leaves APM alone
and lets laptop-mode-tools handle it.

> In my humble opinion you should consider doing something similar in
> acpi-support.

I'll definitely consider adding a switch to -B 128 on battery. However,
I'll have to do some calculation. I know of some laptops that have
9-hour battery lives, and on those laptops the math could be quite
different!

> $sudo install 99-hdd-ugly-fix.sh /etc/acpi/suspend.d/

(This one's not needed BTW.)