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I have this odd behavior that the idle power is either high or low. E.g. sometimes it is 20 W and sometimes 10 W. It stays there until rebooted of suspend/rewake.

All parameters that I know of like backlight, cpu speed, wifi, bluetooth are the same.

Read power using powertop and cat /sys/devices/platform/smapi/BAT0/power_now. They agree on the power.

I'm running archbang x64 (arch with some things preconfigured) on a Lenovo x220 laptop.

Some info from powertop

PowerTOP Version    v2.1
Kernel Version  Linux version 3.7.9-1-ARCH (nobody@foutrelis) (gcc version 4.7.2 (GCC) ) #1 SMP PREEMPT Mon Feb 18 02:13:30 EET 2013
System Name LENOVO 4291P36 ThinkPad X220
CPU Information 4x Intel(R) Core(TM) i5-2520M CPU @ 2.50GHz
OS Information  Arch Linux

** Discharge info during a low state**
Device Power Report

The battery reports a discharge rate of 12.0 W

System baseline power is estimated at 7.47 W

Power est.  Usage   Device name
4.96 W  100.0%  Radio device: iwlwifi
4.74 W   33.3%  Display backlight
4.74 W   12.5%  Display backlight
21.0 mW  0.0 pkts/s Network interface: wlan0 (iwlwifi)
0 mW     1985 rpm   Laptop fan
0 mW    326.8 pkts/s    Network interface: wwan0 (cdc_ncm)
0 mW    275.8 ops/s GPU
0 mW    100.0%  USB device: usb-device-8087-0024
0 mW    100.0%  USB device: EHCI Host Controller
0 mW    100.0%  USB device: F5521gw (Lenovo)
0 mW    100.0%  Radio device: thinkpad_acpi
0 mW     10.9%  CPU use
0 mW     0.0%   Audio codec hwC0D0: Conexant
0 mW     0.0%   Thinkpad light
0 mW     0.0%   USB device: EHCI Host Controller
0 mW     0.0%   USB device: usb-device-8087-0024
0 mW     0.0%   Audio codec hwC0D3: Intel
100.0%  PCI Device: Ricoh Co Ltd MMC/SD Host Controller
100.0%  PCI Device: Intel Corporation Centrino Advanced-N 6205 [Taylor Peak]
100.0%  PCI Device: Intel Corporation 6 Series/C200 Series Chipset Family SMBus Controller
100.0%  PCI Device: Intel Corporation 6 Series/C200 Series Chipset Family 6 port SATA AHCI Controller
100.0%  PCI Device: Intel Corporation QM67 Express Chipset Family LPC Controller
100.0%  PCI Device: Intel Corporation 6 Series/C200 Series Chipset Family USB Enhanced Host Controller #1
100.0%  PCI Device: Intel Corporation 6 Series/C200 Series Chipset Family PCI Express Root Port 5
100.0%  PCI Device: Intel Corporation 6 Series/C200 Series Chipset Family PCI Express Root Port 2
100.0%  PCI Device: Intel Corporation 6 Series/C200 Series Chipset Family High Definition Audio Controller
100.0%  PCI Device: Intel Corporation 6 Series/C200 Series Chipset Family MEI Controller #1
100.0%  PCI Device: Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller
0.0%    PCI Device: Intel Corporation 6 Series/C200 Series Chipset Family PCI Express Root Port 1
0.0%    PCI Device: Intel Corporation 6 Series/C200 Series Chipset Family USB Enhanced Host Controller #2
0.0%    PCI Device: Intel Corporation 2nd Generation Core Processor Family DRAM Controller

And the question: How do I get it to stay at the low mode every time?

share|improve this question

Try

\>rfkill list
0: tpacpi_bluetooth_sw: Bluetooth
        Soft blocked: yes
        Hard blocked: no
1: tpacpi_wwan_sw: Wireless WAN
        Soft blocked: yes
        Hard blocked: no
10: phy1: Wireless LAN
        Soft blocked: no
        Hard blocked: no

Then switch the Radio WAN device with:

rfkill block 1
share|improve this answer
    
Hmm, as I see this, this would softwareblock an already blocked device, why would I want to to this? – Gunnish Mar 4 '14 at 19:28
    
4.96 W 100.0% Radio device: iwlwifi – azul Mar 5 '14 at 20:13

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