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[Francois Thirioux <1289961@xxxxxxxxxxxxxxxxxx>]

I kept BGN mode for my router.

With latest :
3.13.0-20-generic #42-Ubuntu
I get max speed with PM off (somewhat far from my router) and half of it when PM is on. So it is much better but the title of this bug remains open.
The iwlwifi/mac changes in 3.13.7 seem to partially work ?

I noticed that my other laptops (1 with saucy, 1 with precise -- saucy
or raring kernel--) do *not* have PM turned on, without any tweak.
Running trusty, PM is by default turned on.

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https://bugs.launchpad.net/bugs/1289961

Title:
  Power management causes Intel wifi 7260 slowness

Status in “linux” package in Ubuntu:
  Confirmed

Bug description:
  I get a new ThinkPad T440s with Intel 7260 ac wireless.

  The dowload speed reachs an upper limit 400 kB/s instead of the normal
  1500 kB/s I get with some other PC connected to my network. The speed
  often slows down very very low, especially when I'm far away from my
  AP.

  I use Ubuntu Trusty (Gnome) up-to-date.

  Removing N mode does not solve the issue. So I tried removing the
  wireless interface's power management in Powertop and it did solve the
  slowness issue. (iwconfig shows "Power management : off" in this case,
  obviously.)


  lspci************************

  03:00.0 Network controller: Intel Corporation Wireless 7260 (rev 83)

  lshw*************************

  *-network
                  description: Interface réseau sans fil
                  produit: Wireless 7260
                  fabriquant: Intel Corporation
                  identifiant matériel: 0
                  information bus: pci@0000:03:00.0
                  nom logique: wlan0
                  version: 83
                  numéro de série: xxxxxxxxxxx
                  bits: 64 bits
                  horloge: 33MHz
                  fonctionnalités: bus_master cap_list ethernet physical wireless
                  configuration: broadcast=yes driver=iwlwifi driverversion=3.13.0-16-generic firmware=22.24.8.0 ip=192.168.1.21 latency=0 link=yes multicast=yes wireless=IEEE 802.11abgn
                  ressources: irq:61 mémoire:f0400000-f0401fff

  iwconfig*******************************

  wlan0     IEEE 802.11abgn  ESSID:"Livebox"  
            Mode:Managed  Frequency:2.437 GHz  Access Point: xxx   
            Bit Rate=130 Mb/s   Tx-Power=16 dBm   
            Retry  long limit:7   RTS thr:off   Fragment thr:off
            Power Management:on
            Link Quality=60/70  Signal level=-50 dBm  
            Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
            Tx excessive retries:2549  Invalid misc:273   Missed beacon:0

  ifconfig******************************

  wlan0     Link encap:Ethernet  HWaddr xxx
            inet adr:192.168.1.21  Bcast:192.168.1.255  Masque:255.255.255.0
            adr inet6:xxx/64 Scope:Lien
            UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
            Packets reçus:30450 erreurs:0 :0 overruns:0 frame:0
            TX packets:18296 errors:0 dropped:0 overruns:0 carrier:0
            collisions:0 lg file transmission:1000 
            Octets reçus:41761779 (41.7 MB) Octets transmis:1992389 (1.9 MB)

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