Intel Centrino Ultimate-N 6300 supports abg only

[Christophe Dumez]

I installed maverick on my DELL Latitude E4310 which has a Intel Centrino Ultimate-N 6300 wireless card.
I have a Linksys WRT610N router also.

As a consequence, I should be able to connect in 802.11n mode (It works as expected on Windows so this is not a hardware issue).

However, I only get abg modes as you can see:

wlan0 IEEE 802.11abg ESSID:"chris"
          Mode:Managed Frequency:2.412 GHz Access Point: 68:7F:74:9B:3F:50
          Bit Rate=54 Mb/s Tx-Power=15 dBm
          Retry long limit:7 RTS thr:off Fragment thr:off
          Power Management:off
          Link Quality=70/70 Signal level=-39 dBm
          Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
          Tx excessive retries:0 Invalid misc:0 Missed beacon:0

I using the following kernel:
Linux chris-PC 2.6.35-22-generic-pae #33-Ubuntu SMP Sun Sep 19 22:14:14 UTC 2010 i686 GNU/Linux

I tried to install linux-backports-modules-wireless-maverick-generic-pae but it did not help either.

[Christophe Dumez (hydr0g3n)]

I found a way to get it to work:

$ sudo modprobe -r iwlagn
$ sudo modprobe iwlagn 11n_disable=0

Then iwconfig displays:
wlan0 IEEE 802.11abgn ESSID:"chris"
          Mode:Managed Frequency:2.412 GHz Access Point: 68:7F:74:9B:3F:50
          Bit Rate=270 Mb/s Tx-Power=15 dBm
          Retry long limit:7 RTS thr:off Fragment thr:off
          Power Management:off
          Link Quality=64/70 Signal level=-46 dBm
          Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
          Tx excessive retries:0 Invalid misc:0 Missed beacon:0

It seems 11n is disabled as a default !?

[Christophe Dumez (hydr0g3n)]

Hmm.. It seems voluntary:
/etc/modprobe.d/intel-5300-iwlagn-disable11n.conf:options iwlagn 11n_disable=1

Could someone explain why? Is there a known issue when operating in 11n with this card?
I don't seem to experience any problem (yet) but I have been using it for a few minutes only.

[Christophe Dumez (hydr0g3n)]

Ok, side effect of the workaround from https://bugs.launchpad.net/ubuntu/+source/linux-firmware/+bug/630748.

[Fuujuhi (fuujuhi)]

I have similar problem on the same wireless card, however on a HP EliteBook 8540w.

However even when I set the router in B/G-Mixed, or G-only, the laptop refuses to connect, or takes like 1 or 2 min to connect, and then disconnects almost immediately after.

To rule out any hw issue, I booted in Win7, and there the card seems to work fine (at least stable for the 5min I was logged in).

What I tried already:
 - temporarily disabled wireless security
 - tried router in B/G-Mixed, G-Only, B-only.
 - remove & add back iwlagn module, with and without 11n_disabled.

It's on Maverick, with
Linux griffin 2.6.35-24-generic #42-Ubuntu SMP Thu Dec 2 02:41:37 UTC 2010 x86_64 GNU/Linux

What can I do to debug the issue? I don't find any relevant log on the system that I could use to narrow down the problem. I don't care about speed since it's only for internet (so 802.11b/g is ok).

Kind regards

[Whinis (john-p-turner)]

My Intel 6300 Ultimate N works flawlessly in wireless N mode besides taking roughly 1 minute to associate and errors being spewed in log. I get full speed with no slow downs however I do have problems shutting down and restarting as it hangs with no error codes.

[penalvch (penalvch)]

Christophe Dumez, thank you for reporting this and helping make Ubuntu better. This bug was reported a while ago and there hasn't been any activity in it recently. We were wondering if this is still an issue? Can you try with the latest development release of Ubuntu? ISO CD images are available from http://cdimage.ubuntu.com/releases/ .

If it remains an issue, could you run the following command from a Terminal (Applications->Accessories->Terminal). It will automatically gather and attach updated debug information to this report.

apport-collect -p linux <replace-with-bug-number>

Also, if you could test the latest upstream kernel available that would be great. It will allow additional upstream developers to examine the issue. Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Once you've tested the upstream kernel, please remove the 'needs-upstream-testing' tag. This can be done by clicking on the yellow pencil icon next to the tag located at the bottom of the bug description and deleting the 'needs-upstream-testing' text. Please let us know your results.

Thanks in advance.

[Launchpad Janitor (janitor)]

[Expired for linux (Ubuntu) because there has been no activity for 60 days.]

[Fuujuhi (fuujuhi)]

I subscribed to this bug because I experienced similar issue with similar HW. Quite stable connection in Windows and unreliable in Linux.

The fix for me was simply to upgrade the firmware of my wireless router (!!!). Although wireless was working fine with same router in Jaunty (or Karmic, don't remember), I guess it only had a draft-N implementation.

Anyway, upgrading the firmware fixed the problem... 2-yr long problem fixed with a mere upgrade... hum hum silly me ;-)