[ltp] what to use to save battery

[Ari El]

Regarding the 3945 powersaving (iwpriv) options, you can find the
documentation here:

http://ipw3945.sourceforge.net/README.ipw3945

And you can use option 5 if you want maximum powersaving on your wireless
interface.


>> > - enable wireless powersaving
> there are more the one way of enabling this..
> normally i use "iwpriv" for the intel 2200 or 3495 and just try a bit for
> the
> right power mode.

I'm using 7 for the 3495 based on a post I saw here, but I wouldn't
know how to tell if it was "right."  How do you know?  Is it just a
matter of how much reception/transmission power you need to reach the
AP?


David Abrahams wrote:
> 
> Florian Reitmeir <florian@reitmeir.org> writes:
> 
>> On Die, 05 Sep 2006, Martin Aumueller wrote:
>>
>>> These suggestions all seem very interesting. However, could you please 
>>> elaborate on some of them a little bit more?
>> sure
>>
>>> > - a SD Card for the home directory
>> this is easy, just buy one, use the newst kernel and put your home on it.
> 
> Hope you don't mind me asking questions, too... I have a lot to learn.
> 
> Why does that save power?  And why the home directory as opposed to,
> say, /var?
> 
> My laptop doesn't support SD cards directly; I would have to buy a PCI
> card to provide that feature.  Does that nullify the benefit?
> 
>>> > - use the busybox syslog daemon instead of syslogd and klogd
>> The busybox syslogd is nice, it uses a memory buffer for logs. On my
>> laptop
>> there is no need for longterm logfiles. Under debian just install
>> busybox.
>> then use some startup script like:
>>
>> /etc/init.d/sysklogd stop
>> /etc/init.d/klogd stop
>> busybox klogd
>> busybox syslogd -C 16
>>
>> now you can use the command "busybox logread" to get the last 16kb of
>> logs.
> 
> Does that save much over laptop-mode-tools?  My disk seems to spin
> down nicely.
> 
>>> > - disable the internal USB bus for bluetooth and the fingerprint
>>> reader so
>>> > 	the laptop always can use C3/C4 even if the uhci_hcd is loaded (this
>>> can
>>> > be done with unbind in the sysfs)
>>
>> http://lwn.net/Articles/143397/
>>
>> in my thinkpad and X60s there is an internal USBV1 bus, and the kernel
>> activate that bus, because there is the fingerprint reader on it (and
>> bluetooth).
>>
>> just unbind the usb host controller, and the cpu can use C3/C4. To use
>> bluetooth it should fairly simple to script the "bluetooth" button to
>> first
>> bind the bus.. 
> 
> I'll have to ponder that one; sounds like a big win.
> 
>>> > - dim the display
>> thats included in the ibm_acpi kernel module
>>
>>> > - use cpufreq
>> there are normaly 2 drivers
>> acpi cpufreq
>> centrino cpufreq
>>
>> if you want to use undervolting .. you have to disable the acpi cpufreq
>> in
>> your kernel build.
> 
> Hmm, I'm confused.  I've built kernels with the linux-phc patches
> before; I don't remember having to disable anything related to acpi
> cpufreq.  Of course, I was never sure that linux-phc was having an
> effect for me (I have a Core Duo and they haven't worked out the
> mapping from MSR values to voltages definitively yet).
> 
> Since you actually have to patch the kernel to get linux-phc to work,
> and you only mentioned disabling acpi cpufreq, I'm tempted to infer
> from what you wrote that there's another way to get undervolting
> that's built into the stock kernel.  Is that what you're saying?
> 
>>> > - don't use postfix/exim use ssmtp instead
>> postfix/exim do periodic scans of the mail spool. normally i don't need a
>> mailqueue on my notebook. ssmtp is a very simple and direkt MTA which is
>> only
>> active if i send a mail.
> 
> Unfortunately I think I am somewhat tied to exim.  I roam to a number
> of locations where I can only send through one smtp server.  At home,
> my ISP blocks smtp to anywhere but smtp.rcn.com.  At my dad's place,
> it's smtp.comcast.net or nothing.  But in general, you can't use
> either of these servers so I send through my own smtp server that's
> outside any domestic cablemodem network.  I have exim set up to try
> all of these alternatives.  Do you know of a way to get something like
> ssmtp to do the same kind of fallback sequence?
> 
> I might need *some* kind of queueing -- or at least asynchronous
> sending -- anyway because smtp.rcn.com (not to mention the fallback
> sequence) can take annoyingly long to respond sometimes.
> 
>>> > - under gnome, disable beagle
>>
>> if you want to diable your disk when the laptop goes idle, it really is a
>> bad
>> idea to enable beagle .. it becomes active when the disk should spin
>> down..
> 
> I have beagle enabled, AFAICT, and my disk still spins down.  On the
> other hand, beagle seems to have indexed almost nothing on my disk and
> I can't tell why.  Both beagled and beagled-helper are running.
> 
>>> > - use a 2.6.18-rcX kernel and enable alsa-power management
>>
>> the new 2.6.18 kernels have the nice feature for alsa and e1000 modules
>> to
>> disable power until the sound device is open / a network cable is
>> detected.
> 
> Aha.  Maybe I should just skip over 2.6.17, then.  I do see a lot of
> people using 2.6.18.rc2.  I'm just having a really hard time figuring
> out how to build ieee80211 and ipw3945 support for 2.6.17 (especially
> ieee80211, which wants to blow away associated modules for other
> kernel versions when built out-of-tree), but I suppose 2.6.18rcX comes
> with a recent enough ieee80211 that I don't need to install it
> separately.
> 
> Whoa, do you really mean to say that the machine can detect a network
> cable being attached without having the ethernet adapter powered up?
> 
>> for alsa its an compile time option (in the -mm tree)
>> for e1000 its an kernel module option
>>
>>> How do I enable alsa power management? I didn't find a kernel config
>>> option.
>>> 
>>> > - use a 2.6.18-rcX kernel and use the new e1000 module for more
>>> powersaving
>>> 
>>> What does 'new' mean? The one e1000 module that is included with
>>> 2.6.18-rc6 or 
>>> is there another module with a different name?
>>
>> the kernel docu isn't updated yet, but there is a module option:
>>
>> 2.6.18-rc4/drivers/net/e1000/e1000_param.c
>>
>> /* Enable Smart Power Down of the PHY
>>   *
>>   * Valid Range: 0, 1
>>   *
>>   * Default Value: 0 (disabled)
>>   */
>> E1000_PARAM(SmartPowerDownEnable, "Enable PHY smart power down");
> 
> Excellent; I know that powering down the ethernet made a big
> difference on other laptops I've used.
> 
>>> > - enable wireless powersaving
>> there are more the one way of enabling this..
>> normally i use "iwpriv" for the intel 2200 or 3495 and just try a bit for
>> the
>> right power mode.
> 
> I'm using 7 for the 3495 based on a post I saw here, but I wouldn't
> know how to tell if it was "right."  How do you know?  Is it just a
> matter of how much reception/transmission power you need to reach the
> AP?
> 
> -- 
> Dave Abrahams
> Boost Consulting
> www.boost-consulting.com
> 
> -- 
> The linux-thinkpad mailing list home page is at:
> http://mailman.linux-thinkpad.org/mailman/listinfo/linux-thinkpad
> 
> 

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