[Pm-utils] Bug? in pm-powersave
Robby Workman
rw at rlworkman.net
Sun Jan 2 22:35:02 PST 2011
Hi Victor and list,
I think I've encountered a bug in pm-powersave, or maybe it's
a bug in how the powersave hooks are processed, or perhaps I'm
just being braindead ;-) but here's a summary:
My laptop drive doesn't like the default DRIVE_POWER_MGMT_BAT
value of "1" - it goes to sleep every 30 seconds and causes
a delay of 1-2 seconds that makes the system feel like it's
crawling along.
From pm-powersave(8):
FILES
/etc/pm/power.d/, /usr/lib/pm-utils/power.d/
When you run pm-powersave it combines the scripts in
these two directories and executes them in sorted order.
If both directories contain a script with the same name,
the one in /etc/pm/power.d/ has a higher precedence and
only this one will be executed.
Therefore, I grabbed $libdir/pm-utils/power.d/harddrive, placed
a copy at /etc/pm/power.d/harddrive, made sure it retained its
executable permissions, and edited it down to the following:
#!/bin/sh
[ -x /sbin/hdparm ] || exit $NA
DRIVE_WRITE_CACHE_BAT=0
DRIVE_POWER_MGMT_BAT=128
# Default devices to operate on
DRIVE_LIST="/dev/[hs]d[a-z]"
However, when I unplug the AC adapter (or run "pm-powersave true"
manually), the value shown with "hdparm -B /dev/sda" is not 128;
it stays at whatever it was previously. /var/log/pm-powersave.log
shows this:
Running hook /etc/pm/power.d/harddrive true:
/etc/pm/power.d/harddrive true: success.
If I remove the /etc/pm/power.d/harddrive file completely, the
value shown by hdparm afterward is the default value defined in
$libdir/pm-utils/power.d/harddrive, and this is what shows in
/var/log/pm-powersave.log:
Running hook /usr/lib64/pm-utils/power.d/harddrive true:
Enabling power management for /dev/sda...Done.
/usr/lib64/pm-utils/power.d/harddrive true: success.
Am I doing something wrong, or is there a bug here?
-RW
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