RE: ACPI + Laptop Power Management

[Diego SANTA CRUZ <Diego.SantaCruz-p8DiymsW2f8@public.gmane.org>]

On Fri, 2003-11-28 at 04:21, Ow Mun Heng wrote:

> The thing here is, even though it's flushing the buffers when there are
> others to flush, it makes not difference if the drive is still spinning and
> not in standby-mode! I can't figure out what is making the HD _not_ spin
> down.
> 

Just a thing to check: syslogd will (by default) sync the log file after
each write. If you have a daemon that write syslog messages often then
syslogd will keep your HD active all the time, despite any laptop-mode.

Two, possibly complementary, solutions

1) Find the offending daemon(s) and modify their settings or disable
them if not necessary.

2) Prepend the log file name with a - on the /etc/syslog.conf file. This
prevents the sync on every write default.

If this does not solve your problem you can check (in dmesg) what is
writing to disk by doing

echo -n 1 > /proc/sys/vm/block_dump

But BE CAREFUL!. You have to disable klogd before doing this or you will
likely end up in an infinite loop.

Hope this helps.
-- 
-------------------------------------------------------
Diego Santa Cruz - PhD
Publications available at http://ltswww.epfl.ch/~dsanta
Signal Processing Institute (LTS1 / ITS / STI)
Swiss Federal Institute of Technology (EPFL)
EPFL - STI - ITS, CH-1015 Lausanne, Switzerland
E-mail:     Diego.SantaCruz-p8DiymsW2f8@public.gmane.org
Phone:      +41 - 21 - 693 26 57
Fax:        +41 - 21 - 693 76 00
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