[SOLVED] Cpu frequency scaling not working when power adaptor not charging

michal017 · 01-25-2013, 02:00 AM

I have Dell D630 laptop and my power adaptor has some issue and it is not charging the battery, so laptop is running on AC power but not charging the battery. The problem is, the CPU is always on the lowest frequency.
When I use other adaptor, which charges the battery as well, cpu freq scaling works normally. Do you know what needs to be configured?
I'm on Debian unstable.

Snark1994 · 01-25-2013, 04:40 PM

This is almost certainly the laptop mode tools package which you need to configure. Do you have the file "/etc/acpi/handler.sh"?

michal017 · 01-25-2013, 05:08 PM

No, I don't.

Snark1994 · 01-26-2013, 06:45 AM

Okay, well, I've found http://packages.debian.org/sid/all/l...tools/filelist. Perhaps it might be in

Code:

/etc/acpi/actions/lm_ac_adapter.sh
/etc/acpi/actions/lm_battery.sh

You're looking for code along the lines of

Code:

 ac_adapter)
     case "$2" in
         AC*)
             case "$4" in
                 00000000)
                     echo "conservative" >/sys/devices/system/cpu/cpu0/cpufreq/scaling_governor    
                     echo -n $minspeed >$setspeed
                     #/etc/laptop-mode/laptop-mode start
                 ;;

(particularly the 'echo "conservative"' part).

Another possibility is /etc/laptop-mode/conf.d/cpufreq.conf - that may have lines similar to:

Code:

BATT_CPU_GOVERNOR=conservative
...
LM_AC_CPU_GOVERNOR=ondemand
...
NOLM_AC_CPU_GOVERNOR=ondemand

which can be tweaked to select an appropriate governor when the laptop thinks it's running on battery.

michal017 · 01-30-2013, 04:37 AM

I have all the *_CPU_GOVERNOR set to ondemand, so CPU freq should scale regardless of the power. But it does not.

michal017 · 02-02-2013, 04:18 PM

Finally figured it out. E17 starts all apps with nice 3 by default, and the default CPU configuration on Debian seems to set ignore nice load on battery. Once I changed this, CPU freq scaling works.