bad wifi connection with Lenovo X240 under Ubuntu 14.04 --- intel wireless 7260

Question

On my Lenovo X240 I have installed Ubuntu 14.04. Everything, including the LAN connection, works very smoothly except from the WiFi.

The computer connects to a WiFi hotspot but after a few bytes transmitted the connection breaks down completely.

EDIT: --> If the hotspot is less crowded, i.e. if I switch off my other clients, then the connection works more or less stable but still with occasional troubles. <--

The hotspot is OK, since other devices do not experience any troubles.

Any ideas? I am not too deep in Ubuntu, please give me advice if you need more information on the hardware.

This is what iwconfig gives me:

iland@note121:~$ iwconfig
eth0      no wireless extensions.

lo        no wireless extensions.

wlan0     IEEE 802.11abgn  ESSID:"thrasher(at)hajod.de"  
          Mode:Managed  Frequency:2.412 GHz  Access Point: 7C:4F:B5:C8:D2:C4   
          Bit Rate=54 Mb/s   Tx-Power=16 dBm   
          Retry  long limit:7   RTS thr:off   Fragment thr:off
          Power Management:on
          Link Quality=70/70  Signal level=-35 dBm  
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:6   Missed beacon:0

And this the hardware configuration from sudo lshw -c network:

 *-network               
       description: Ethernet interface
       product: Ethernet Connection I218-LM
       vendor: Intel Corporation
       physical id: 19
       bus info: pci@0000:00:19.0
       logical name: eth0
       version: 04
       serial: 28:d2:44:40:96:64
       size: 100Mbit/s
       capacity: 1Gbit/s
       width: 32 bits
       clock: 33MHz
       capabilities: pm msi bus_master cap_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt-fd autonegotiation
       configuration: autonegotiation=on broadcast=yes driver=e1000e driverversion=2.3.2-k duplex=full firmware=0.6-3 ip=192.168.1.11 latency=0 link=yes multicast=yes port=twisted pair speed=100Mbit/s
       resources: irq:61 memory:f0600000-f061ffff memory:f063e000-f063efff ioport:3080(size=32)
  *-network
       description: Wireless interface
       product: Wireless 7260
       vendor: Intel Corporation
       physical id: 0
       bus info: pci@0000:03:00.0
       logical name: wlan0
       version: 83
       serial: 5c:51:4f:58:a5:c5
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless
       configuration: broadcast=yes driver=iwlwifi driverversion=3.13.0-24-generic firmware=22.24.8.0 ip=192.168.1.10 latency=0 link=yes multicast=yes wireless=IEEE 802.11abgn
       resources: irq:66 memory:f0400000-f0401fff

Solution

You could try this:

iwconfig wlan0 retry short 21

iwconfig wlan0 retry long 21

If the driver is working well, this should help, if not..

Try reorienting the antenna (turn the laptop 45 degrees or so and see if it makes a difference)

Comments

[user100464]

As I understand it, the Wifi driver is from Intel, and they're aware of the problem: communities.intel.com/message/220504

[Jan]

thanks for your hint... I will keep track of this discussion.

[bain]

Ubuntu bug #1305305

[MadMike]

Could you explain how to install the mainline kernel 3.19 on a Ubuntu 14.04?

[enjoy]

@MadMike here is an example to install mainline kernel 3.13.0-999 ...