Dell Precision m4400 acline problems

[Stefan Farfeleder]

On Tue, Jun 22, 2010 at 01:36:03AM +1000, Ian Smith wrote:
> 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?

Thanks. I think I solved my problem. I do not use power profiles and
thus the dev.cpu.0.freq stays at 2801. However going offline evidently
causes the frequency to decrease internally, ie. without dev.cpu.0.freq
knowing, so when I manually reset the frequency to 2801, the system is
fast again.

Cheers,
Stefan