Power-drain during suspend?

[Kevin Oberman]

> Date: Sat, 11 Feb 2006 11:54:38 +0100
> From: Tobias Roth <roth at iam.unibe.ch>
> Sender: owner-freebsd-mobile at freebsd.org
> 
> On Fri, Feb 10, 2006 at 03:03:30PM -0800, Kevin Oberman wrote:
> > > Date: Fri, 10 Feb 2006 22:06:15 +0100
> > > From: Gregers Petersen <gp.ioa at cbs.dk>
> > > Sender: owner-freebsd-mobile at freebsd.org
> > > 
> > > Kevin Oberman wrote:
> > > 
> > > >>>>> hw.pci.do_power_nodriver=[1|2|3]
> > > 
> > > I have been changing the setting of the above to '3' - and done a bit of 
> > > "testing" with suspend/resume.
> > > The result is not much different from before, the R51 still "eats" the 
> > > battery after 6-7 hours of suspend :-/
> > > I have tried to suspend without X.org running to test if this had any 
> > > effect, but there is no clear difference - and I end up with pusslement.
> > > 
> > > Any suggestions about what else I could try out ?
> > 
> > Are you using radeontool and turning off both the DAC and the display
> > (assuming you have a Radeon video chip)? It saves a quite a bit of
> > power. Other than that, I'm not sure what to suggest.
> > 
> > Sorry, but maybe someone else has a better idea. 
> 
> Wasn't there an issue with usb drivers not being able to properly
> shut down and put into powersave mode all connected devices? Has
> that been remedied?
> 
> If not you could try removing everything usb-related from your
> kernel, and making sure no usb modules are loaded and test again.

Must be senility! You REALLY need to have no USB driver active. It eats
lots of power whether the system is active or suspended.

I build the kernel for my laptop without USB (or any of the drivers that
depend on it) and load them when needed. You can just load the "top
level" driver like umass or ucom. Any drivers (like usb) that are
needed by that driver should be auto-loaded.

Also, make sure to set:
economy_cx_lowest="LOW"
LOW is now default in -current, but I don't think is is in -stable.

CX levels are for general battery life and not specific to suspend,
though. It does slightly degrade performance, but it has never bothered
me as it only kicks in when the CPU is idle for fairly long periods.
-- 
R. Kevin Oberman, Network Engineer
Energy Sciences Network (ESnet)
Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab)
E-mail: oberman at es.net			Phone: +1 510 486-8634