WiFi problems (intell centrino 6200) on X201

[lparsons]

I've been having some really frustrating wireless problems on my X201 (laptop, not tablet) in recent months. I run Kubuntu as my main OS, and it started after I upgraded to 14.04 LTS. I would notice that at times the wireless card would just "disappear"; running ifconfig at a command prompt would no longer show "wlan0" entries at all. Generally the older version of Kubuntu would not show this problem. Generally the card would work at first boot and at some point later just disappear.

So for a while I would run 14.04 at work (where I was on wired via a docking station) and not worry about it, then run 13.04 at home (where I was only using wireless). Along the way I tried various "fixes" such as having Kubuntu 14.04 load a different firmware for the card, this made no difference. Eventually I found the card wasn't working in 13.04 either. Sometimes the behavior was the same - worked at first then eventually disappeared - and some times it wouldn't come up at all.

Out of desperation I booted Win7 64bit Pro (came on the laptop). I now see Windows doesn't see it either. This suggests to me that I have a hardware problem. I pulled the miniPCI wireless card and reseated it, which didn't help. I found replacement wireless cards on ebay (through a local supplier) and tried one, which didn't help either. I found someone else who suggested pulling the CMOS battery (http://forum.notebookreview.com/lenovo/ ... ues-2.html) which also didn't help.

I'm wondering if I may need to consider replacing the motherboard? The system is otherwise working great. I bought it used over a year ago now and other than the wireless problem it's been solid.

[lparsons]

Shortly after posting this I noticed that the first time I booted into Ubuntu 14.04 after disconnecting (and reconnecting) my CMOS battery the wifi adapter was seen but for unknown reasons not initiated. I then started it from the panel and it has been working fine since. I can't explain why wiping out the BIOS memory like that would help but so far, so good... I of course had to go in and set the system time/date manually the first time I booted after doing that but otherwise things seem good.

[lparsons]

Well, that worked for almost three days (2 days 19hours was the posted uptime). Then with no warning the wlan0 interface went away in Ubuntu. I saw a message on my desktop saying that I was not connected to my wifi router, and ifconfig showed no interface. The most relevant bits I could find from dmesg:

Code: Select all

[243214.398805] iwlwifi 0000:02:00.0: RF_KILL bit toggled to disable radio.
[243214.398931] wlan0: deauthenticating from 48:f8:b3:09:62:7f by local choice (reason=3)
[243214.398994] iwlwifi 0000:02:00.0: Not sending command - RF KILL
[243214.398999] wlan0: failed to remove key (0, 48:f8:b3:09:62:7f) from hardware (-5)
[243214.399116] iwlwifi 0000:02:00.0: Not sending command - RF KILL
[243214.399123] iwlwifi 0000:02:00.0: Not sending command - RF KILL
[243214.399129] iwlwifi 0000:02:00.0: Not sending command - RF KILL
[243214.399163] iwlwifi 0000:02:00.0: Not sending command - RF KILL
[243214.399177] iwlwifi 0000:02:00.0: Not sending command - RF KILL
[243214.399208] iwlwifi 0000:02:00.0: Not sending command - RF KILL
[243214.399213] wlan0: failed to remove key (1, ff:ff:ff:ff:ff:ff) from hardware (-5)
[243214.399272] iwlwifi 0000:02:00.0: Not sending command - RF KILL
[243214.399294] wlan0: failed to remove key (2, ff:ff:ff:ff:ff:ff) from hardware (-5)
[243214.419590] usb 1-1.4: USB disconnect, device number 8
[243214.474317] iwlwifi 0000:02:00.0: Not sending command - RF KILL
[243214.475125] IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready

I powered down my laptop, and booted back in to Ubuntu, no luck. I then powered down and booted windows instead, and things were OK. Then I powered down again and went back to Ubuntu and my wireless is back.

[RealBlackStuff]

Since this apparently is a Linux problem, I have moved it to the Linux-forum.

[lparsons]

I'm not sure that it is a Linux problem, as the Linux solutions don't work. I think the fact that it occasionally works in Windows is a red herring in this case.

Now, whether the problem is the wifi card or something else, I'm not sure yet.