Unstable wifi on battery

robbiedobbie · 2013-08-23 17:58:17

Hi all,

Recently I started having problems with my laptop's wifi. It started losing packets, which caused the network being very unstable, even when I am standing next to the router. However, it did not do this all the time. This made it hard to debug. After some weeks, I now found out that it has to do with running on battery. If I run on battery, packets drop and when I run with the power cable attached, the wifi is just fine.

I have an Alienware M17x R4 running arch linux in combination with xfce. My wireless card is the Intel Corporation Centrino Wireless-N 2230 (rev c4).

I made 2 test reports with mtr connecting to google, to compare the situation with and without powercable. You can clearly see the difference.

(I removed the Ip's and domain names for privacy reasons)

With powercable:

HOST: LaptopRob                   Loss%   Snt   Last   Avg  Best  Wrst StDev
  1.|-- ???                       100.0    10    0.0   0.0   0.0   0.0   0.0
  2.|-- ???                       100.0    10    0.0   0.0   0.0   0.0   0.0
  3.|--                            0.0%    10    9.7   9.6   7.3  17.4   3.5
  4.|--                            0.0%    10    9.9  13.8   9.4  44.9  10.9
  5.|--                            0.0%    10   14.9  13.8  12.2  15.2   0.7
  6.|--                            0.0%    10   13.6  13.8  12.4  15.4   0.7
  7.|--                            0.0%    10   16.7  15.5  11.4  24.7   4.7
  8.|--                            0.0%    10   14.1  15.8  12.9  23.1   3.6
  9.|--                            0.0%    10   16.9  18.9  16.4  26.7   4.0
 10.|-- ???                       100.0    10    0.0   0.0   0.0   0.0   0.0
 11.|--                            0.0%    10   17.9  20.2  16.7  30.7   4.9

without powercable:

HOST: LaptopRob                   Loss%   Snt   Last   Avg  Best  Wrst StDev
  1.|-- ???                       100.0    10    0.0   0.0   0.0   0.0   0.0
  2.|-- ???                       100.0    10    0.0   0.0   0.0   0.0   0.0
  3.|--                            0.0%    10   20.0  70.6  20.0 106.3  31.0
  4.|--                           90.0%    10  479.8 479.8 479.8 479.8   0.0
  5.|--                           90.0%    10  356.1 356.1 356.1 356.1   0.0
  6.|--                           60.0%    10  428.8 695.3 237.7 1431. 523.6
  7.|--                           50.0%    10  337.4 701.5 112.1 1340. 516.0
  8.|--                           50.0%    10  245.9 444.4  14.7 986.4 362.3
  9.|--                           50.0%     8  154.5 533.4 154.5 1158. 435.4
 10.|-- ???                       100.0     8    0.0   0.0   0.0   0.0   0.0
 11.|--                           37.5%     8   16.3 697.8  16.3 1978. 801.7

I also tried turning the powersave off with

iw wlp8s0 set power_save off

but this didn't make any difference.

Does anyone know how to solve this?

Last edited by robbiedobbie (2013-08-23 17:58:45)

WonderWoofy · 2013-08-23 18:59:38

Do you use something like laptop-mode-tools or tlp which might be changing the power saving features when you plug/unplug your system? It seems to me that there *should* be no change in the configuration of the wirless card unless you have something that is deliberately doing so.

robbiedobbie · 2013-08-23 19:59:21

Both laptop-mode-tools and tlp are not installed. However, xfce did install a power manager, but I can't find any settings related to wifi... Also, removing xfce4-power-manager does not change anything.

Last edited by robbiedobbie (2013-08-23 20:03:13)

WonderWoofy · 2013-08-24 00:28:37

I have no idea what it mght do, but xfce4-power-manager also installs upower.

How about this. Can you boot up to the multi-user.target (hopefully without also starting any of teh xfce4 stuff -- particularly upower) and then use the internets from there. See if the battery powered machine in the multi-user.target acts the same way. I'd suggest even using basic networking tools to connect, though I think netctl would also do the trick, since it is just a set of shell scripts around those tools.

I also have an Intel Centrino 2230, and it was a great card (I have since moved on to the only dual band card that is usable with my machine). I do have a coupel friends though who had nothing but problems with the iwlwifi module in general. I have seen a lot of work going into the iwlwifi module in terms of kernel commits, so hopefully things are getting better. I have been meaning to give that card another go, just to see. Maybe I'll do that sometime this weekend. If I get around to it, I'll report back on how things are with 3.11rc6.

robbiedobbie · 2013-08-24 08:08:36

Hmm, I tried removing upower and all depending packages. This did solve my problem, however, upower is used not only in xfce4-power-managar but also in usefull libraries like kdelibs (I was using it for libreoffice) and the gnome-settings daemon. My problem now is, that I both need stable wifi, and things like libreoffice which depend on them.

I will start searching for solving this problem myself, but if anyone knows how I can solve this problem, please leave a message

Also, WonderWoofie, thank you for your help already!

EDIT: After some more testing, I found out that it was probably coincidence that something in the system did not go to powersavings or something. I still have the problem without upower...

Last edited by robbiedobbie (2013-08-24 08:59:42)

Arch Linux

#1 2013-08-23 17:58:17

Unstable wifi on battery

#2 2013-08-23 18:59:38

Re: Unstable wifi on battery

#3 2013-08-23 19:59:21

Re: Unstable wifi on battery

#4 2013-08-24 00:28:37

Re: Unstable wifi on battery

#5 2013-08-24 08:08:36

Re: Unstable wifi on battery

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