Dell Precision m4400 acline problems

[Ian Smith]

On Sun, 20 Jun 2010, Stefan Farfeleder wrote:
 > Hello,
 > 
 > I'm running FreeBSD current on a Dell Precision m4400 notebook and got
 > the following issue: When I unplug the notebook's power, the CPU
 > performance goes down to < 50%. While this isn't nice, the real problem
 > is that when I replug the power adapter, the performance stays low. So I
 > basically have to reboot to get back at full performance :(
 > 
 > I suspect this is an ACPI-related problem.  You can find dmesg output,
 > ACPI tables and ASL at http://people.freebsd.org/~stefanf/m4400/ .
 > 
 > BTW I'm not using powerd.

Whether or not using powerd, /etc/rc.d/power_profile (run by devd) will 
set CPU frequency according to values in {performance,economy}_cpu_freq 
whenever state changes between offline (battery) and online (AC).  Such 
events are typically logged in /var/log/messages.

The /etc/defaults/rc.conf value for both of these is 'NONE' and you'll 
see in power_profile that a 'NONE' value causes no change, where 'HIGH" 
or 'LOW' values adjust CPU freq to the highest or lowest values from
sysctl dev.cpu.0.freq_levels - or you can specify one freq from those 
levels to apply for either state.

If you have no overrides in /etc/rc.conf, you may want to set values 
there for *_cpu_freq .. it may be that your ACPI chooses some default 
frequency on these events, perhaps according to your BIOS settings?

cheers, Ian