iwlagn won't do wireless N

[abeowitz]

I've got an Intel 1000 Wireless N chip:

03:00.0 Network controller: Intel Corporation Centrino Wireless-N 1000

It connects to G networks just fine. But will not connect to a Wireless N AP.

iwconfig suggests it's only doing b/g:

wlan0     IEEE 802.11bg  ESSID:"abeowitz"  
          Mode:Managed  Frequency:2.437 GHz  Access Point: 68:7F:74:9A:F1:30   
          Bit Rate=54 Mb/s   Tx-Power=14 dBm   
          Retry  long limit:7   RTS thr:off   Fragment thr:off
          Encryption key:off
          Power Management:off
          Link Quality=58/70  Signal level=-52 dBm  
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:0   Missed beacon:0

Firmware is up to date.

md5sum iwlwifi-1000-3.ucode

df79176a88147862c5fe2b7f81c11711  iwlwifi-1000-3.ucode

I tried Arch-Linux on this same laptop and got it to do N just fine. Even got up to 130Mb/s in iwconfig output!

So,

1) Firmware is good, same as Arch linux
2) AP is good, others connect fine at N speeds
3) G connects fine, so not authentication or other logical problem...

What should I look for?

Ubuntu 10.10 64 bit

2.6.35-22-generic

[abeowitz]

root@abe-U43Jc:~# dmesg | grep -i iwl
[    3.620032] iwlagn: Intel(R) Wireless WiFi Link AGN driver for Linux, in-tree:
[    3.620035] iwlagn: Copyright(c) 2003-2010 Intel Corporation
[    3.620150] iwlagn 0000:03:00.0: PCI INT A -> GSI 17 (level, low) -> IRQ 17
[    3.620189] iwlagn 0000:03:00.0: setting latency timer to 64
[    3.620290] iwlagn 0000:03:00.0: Detected Intel(R) Centrino(R) Wireless-N 1000 BGN, REV=0x6C
[    3.644059] iwlagn 0000:03:00.0: Tunable channels: 13 802.11bg, 0 802.11a channels
[    3.644433] iwlagn 0000:03:00.0: irq 47 for MSI/MSI-X
[    3.687821] iwlagn 0000:03:00.0: loaded firmware version 128.50.3.1 build 13488
[    3.719619] phy0: Selected rate control algorithm 'iwl-agn-rs'

[Mobidoy]

I have the same issue with a Intel(R) WiFi Link 5100 AGN, it will connect on mixed mode but not on N only

[ABCC]

I've encountered the same problem on an Intel 5100, once I'd switched my access point to both N and G allowed me to atleast connect again.

Looking through some old messages from 10.04 I found that a similar note about configurable channels appeared:

~ # zgrep iwl /var/log/messages.3.gz
...
kernel: [   28.670384] iwlagn 0000:04:00.0: Detected Intel Wireless WiFi Link 5100AGN REV=0x54
kernel: [   28.728369] iwlagn 0000:04:00.0: Tunable channels: 13 802.11bg, 24 802.11a channels
kernel: [   31.370171] iwlagn 0000:04:00.0: firmware: requesting iwlwifi-5000-2.ucode
kernel: [   31.413115] iwlagn 0000:04:00.0: loaded firmware version 8.24.2.12

Again no N channels mentioned, yet my AP was set to N only and everything worked as expected. It seems that not listing N under "tunable channels" doesn't preclude it from working.

[abeowitz]

GOT IT!!!!

The iwlagn module might have 'n' disabled by accident...

rmmod iwlagn

modprobe iwlagn 11n_disable=0

iwconfig

lo        no wireless extensions.

eth0      no wireless extensions.

vboxnet0  no wireless extensions.

wlan0     IEEE 802.11bgn  ESSID:"abeowitz"  
          Mode:Managed  Frequency:2.437 GHz  Access Point: 68:7F:74:9A:F1:30   
          Bit Rate=135 Mb/s   Tx-Power=14 dBm   
          Retry  long limit:7   RTS thr:off   Fragment thr:off
          Encryption key:off
          Power Management:off
          Link Quality=49/70  Signal level=-61 dBm  
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:0   Missed beacon:0

[abeowitz]

Looks like /etc/modprobe.d/intel-5300-iwlagn-disable11n.conf is our culprit.

Delete or move this file.

wlan0     IEEE 802.11bgn  ESSID:"abeowitz"  
          Mode:Managed  Frequency:2.437 GHz  Access Point: 68:7F:74:9A:F1:30   
          Bit Rate=150 Mb/s   Tx-Power=14 dBm   
          Retry  long limit:7   RTS thr:off   Fragment thr:off
          Encryption key:off
          Power Management:off
          Link Quality=50/70  Signal level=-60 dBm  
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:0   Missed beacon:0

[Mobidoy]

Awesome, it works for me too I have set my router to N only and I connect

So deleting this file makes it a permanent fix ?

[abeowitz]

Mobidoy,

Yes, deleting the file is a permanent fix.

Not sure why it's there to begin with, perhaps cruft leftover from testing or a bug with the 5300.

-Abe

[sumerland]

Yes, it's a feature and not a bug:

"802.11n support for the iwlagn driver has been temporarily disabled. Intel is actively working to get this properly fixed up in the firmware. This workaround should be reverted once updated firmware is available."

Or visit this link: https://bugs.launchpad.net/ubuntu/ma...re/+bug/630748

[abeowitz]

Yes, it's a feature and not a bug:

"802.11n support for the iwlagn driver has been temporarily disabled. Intel is actively working to get this properly fixed up in the firmware. This workaround should be reverted once updated firmware is available."

Or visit this link: https://bugs.launchpad.net/ubuntu/ma...re/+bug/630748

Awesome! Thanks for the info! If I have problems with N, I'll know how to disable then.