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#1 2014-10-29 00:50:20

nickaubert
Member
Registered: 2014-10-29
Posts: 2

iwlwifi power usage on Lenovo X230

I'm getting serious power drain from the wireless interface on my Lenovo X230.  Powertop reports between 5 and 7W.

My wireless card is an Intel Centrino-N 2200:
# lspci | grep 'Network controller'
03:00.0 Network controller: Intel Corporation Centrino Wireless-N 2200 (rev c4)

I'm running the latest Con Kolivas 3.16 kernel
# uname -a
Linux pnut 3.16.6-3-ck #1 SMP PREEMPT Wed Oct 22 21:33:53 EDT 2014 x86_64 GNU/Linux

I've tried the stock kernel as well, and it has the same effect.

I've disabled 802.11n
# cat /sys/module/iwlwifi/parameters/11n_disable
1

Wireless power savings is on
# iw dev wlp3s0 get power_save
Power save: on

The power drain seems to have gotten significantly worse recently, because I remember it being closer half a watt in the past.  Perhaps a kernel or driver update was responsible? Is there anything else I should be looking at?

Thanks.

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#2 2014-10-29 13:31:41

brix
Member
Registered: 2014-05-26
Posts: 69

Re: iwlwifi power usage on Lenovo X230

This is pretty much what I've always seen (Lenovo Yoga 2 Pro w. Intel wireless-N, currently linux 3.17.1-1, power management on):

PowerTOP 2.6.1    Overview   Idle stats   Frequency stats   Device stats   Tunables                                     

The battery reports a discharge rate of 8.78 W
The estimated remaining time is 4 hours, 41 minutes

Summary: 293.1 wakeups/second,  9.9 GPU ops/seconds, 0.0 VFS ops/sec and 4.4% CPU use

Power est.              Usage       Events/s    Category       Description
  5.90 W     12.7 pkts/s                Device         Network interface: wlp1s0 (iwlwifi)
  3.86 W    100.0%                      Device         USB device: USB Receiver (Logitech)
  614 mW     58.0%                      Device         Display backlight
  517 mW     12.5 ms/s      90.6        Process        /usr/bin/Xorg.bin <snip>

A little puzzling, admittedly:
- the power-hungry (relative to what it's accomplishing) Logitech wireless mouse receiver, and
- the fact that the top two consumption rates add up to more than the total consumption rate.


Enough is more.

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#3 2014-11-04 23:45:21

nickaubert
Member
Registered: 2014-10-29
Posts: 2

Re: iwlwifi power usage on Lenovo X230

If anyone is following along or experiencing the same issue, I downloaded and compiled the 3.14.23-1-lts-ck kernel, and now my network interface is using half a Watt.  I don't know if it's due to the version or some compilation flat, but this is definitely kernel related.

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