best ways to use powertop?

[marko]

I've been wanting to find out how to best minimize power
waste on my laptop. For example my T41 has bluetooth,
a ipw2100 (intel wireless) and a e1000 (wired gbit ethernet),
when I'm at the wireless cafe, I have no use for the e1000
but only want the ipw2100 running. The bluetooth and
software modem (Intel 82801DB-ICH4 AC97 Modem)
I never have a use for at all. So I'd like the bluetooth and
modem hardware to be off always. The first thing I did
was turn off the bluetooth support stuff:

chkconfig bluetooth off
chkconfig hidd off

But does this really turn off the hardware?

I then tried running powertop http://www.linuxpowertop.org
(you can install with "yum install powertop" I went with
the one on the F7 updates repo instead of main repo because
it was much newer.

and it gives hints to do:

1) hal-disable-polling --device /dev/scd0
2) echo 1 > /sys/module/snd_ac97_codec/parameters/power_save
3) use noatime option in the /etc/fstab to reduce writing time stamps
to files when they are just looked at.


So I've edited the /etc/fstab to add noatime options for the real disk partitions
( / /boot and /home ) and I've got a script that I may have the
boot process run via rc.local to do the #1 and #2 I've listed
above.

But what I'd also like to completely turn off the bluetooth and the dumb
software modem in my T41.

PowerTOP version 1.7 (C) 2007 Intel Corporation

Cn Avg residency (0s) P-states (frequencies)
C0 (cpu running) ( 2.8%)
C1 0.0ms ( 0.0%) 1.60 Ghz 0.0%
C2 7.0ms (97.2%) 1400 Mhz 0.0%
C3 0.0ms ( 0.0%) 1200 Mhz 0.0%
600 Mhz 100.0%

Wakeups-from-idle per second : 137.3
no ACPI power usage estimate available

Top causes for wakeups:
45.0% ( inf) <interrupt> : yenta, yenta, uhci_hcd:usb1, uhci_hcd:usb2, uhci_hcd:usb3, ehci_hcd:usb4, eth1, radeon@pci:0000:01:00.0, Intel 82801DB-ICH4, Intel 82801DB-ICH4 Modem,
10.0% ( inf) konsole : schedule_timeout (process_timeout)
5.0% ( inf) <interrupt> : i8042
5.0% ( inf) dhcdbd : schedule_timeout (process_timeout)
5.0% ( inf) ipw2100/0 : __netdev_watchdog_up (dev_watchdog)
5.0% ( inf) ip : e1000_intr (e1000_watchdog)
5.0% ( inf) <kernel module> : neigh_table_init_no_netlink (neigh_periodic_timer)
5.0% ( inf) sh : queue_delayed_work_on (delayed_work_timer_fn)
5.0% ( inf) X : do_setitimer (it_real_fn)
5.0% ( inf) artsd : schedule_timeout (process_timeout)
5.0% ( inf) wpa_supplicant : schedule_timeout (process_timeout)

Unfortunately that 45% line doesn't break down which of those is
the bigger cause. Some discussion on the powertop forum
says the radeon driver wakes up the laptop a lot. But then
I was getting into C2 97% of the time (that was mostly integrated with
me in KDE, firefox running and no USB devices and not using the
keyboard or mouse (the T41 pointer) so I'm probably doing
pretty well.
Mark

[stevea]

1/ Nice package - thanks for the note.
2/ If the drivers aren't loaded then the device is abt as "off" as it can get.
3/ I have a t42 w/no bluetooth, and I get non/zero for e1000 using network manager.
despite this I have

[root@nidula etc]# lsmod | grep e1000
e1000 118401 0

[edit add]
I did

rmmod ehci_hcd
rmmod uhci_hcd

which broke all the USB devices, but had zero effect on the number of wakeups per sec.


Note that the "Intel 82801DB-ICH4 Modem" is the ac_97 sound card stuff and not the conexant.
You could try to remove the *snd* modules in "lsmod", but I strongly suspect this makes no difference in power usage since you already .. "echo 1 > /sys/module/snd_ac97_codec/parameters/power_save".

If you are concern abt the conexant turn it (both serial lines) off in the bios.

--

Here is a little script I call "batt":.

#!/bin/bash
cat /proc/acpi/battery/BAT0/state

If you execute it in while on battery only is shows a very a high resolution discharge rate.
IMO the greatest battery savings are from turning off the wireless802.11 and turning down the display brightness. I have no bluetooth so ....