Problem with powersaving stuff in rc.local

Question

Hi,
I have a strange problem with the entries in my rc.local which are relevant for powersaving. First the file, which looks like this:
#!/bin/bash
# /etc/rc.local: Local multi-user startup script.
#avoid hdd spindown for longer life :)
hdparm -B 254 -S 0 /dev/sda
#set lower cpu voltages
echo "25 23 21 17" > /sys/devices/system/cpu/cpu0/cpufreq/phc_vids
echo "25 23 21 17" > /sys/devices/system/cpu/cpu1/cpufreq/phc_vids
#use sata link power management
echo "min_power" > /sys/class/scsi_host/host0/link_power_management_policy
echo "min_power" > /sys/class/scsi_host/host1/link_power_management_policy
echo "min_power" > /sys/class/scsi_host/host2/link_power_management_policy
echo "min_power" > /sys/class/scsi_host/host3/link_power_management_policy
#set power saving mode for hda_intel
echo 1 > /sys/module/snd_hda_intel/parameters/power_save
#increase writeback time to 15s
echo 1500 > /proc/sys/vm/dirty_writeback_centisecs
#disable unused outputs
xrandr --output DP1 --off
xrandr --output DP2 --off
xrandr --output TV1 --off
xrandr --output HDMI1 --off
#enable kernel laptop mode for i/o
echo 5 > /proc/sys/vm/laptop_mode
#enable wlan power saving mode
iwconfig wlan0 power on
Not e.g. the phc_vids are written correctly, which means that they are exactly what I set in rc.local when I check them. Same goes for hda_intel powersave, but e.g. the line
echo 5 > /proc/sys/vm/laptop_mode
(is 0 when I check it after booting) or the link_power_management_policy stuff (is set to max_performance when I check it) seem to have no influence. Though, when I set these manually, they work like a charm.
Does anyone have an idea why this happens? Thanks in advance

Answer 1

Hi Singul,
just a wild guess - but maybe it could help, to issue the commands, which doesn't work, with "sleep". I played around with it myself some time ago and it helps to start some processes when the computer / hard drive isn't stressed as much after booting the system. It's worth a try.
Example:
sleep 60 && echo 5 > /proc/sys/vm/laptop_mode &