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Using either NetworkManager or Wicd to manage wireless networking on my Wi-Fi-powered laptop, too often I get randomly disconnected, and I see these messages on /var/log/syslog:

Dec 10 05:21:26 debian dhclient: DHCPREQUEST on wlan0 to port 67
Dec 10 05:21:26 debian dhclient: DHCPACK from
Dec 10 05:21:26 debian dhclient: bound to -- renewal in 1662 seconds.
Dec 10 05:40:38 debian kernel: [105982.935232] iwlagn 0000:06:00.0: Microcode SW error detected.  Restarting 0x82000000.
Dec 10 05:40:38 debian kernel: [105983.182330] Registered led device: iwl-phy0::radio
Dec 10 05:40:38 debian kernel: [105983.182586] Registered led device: iwl-phy0::assoc
Dec 10 05:40:38 debian kernel: [105983.182658] Registered led device: iwl-phy0::RX
Dec 10 05:40:38 debian kernel: [105983.182872] Registered led device: iwl-phy0::TX

I think 05:40:38 is the first line that indicates trouble

With NetworkManager, I recover from this situation with the following command each time this happens:

nmcli nm wifi off && nmcli nm wifi on

Output of uname -a:

Linux debian 2.6.32-5-686-bigmem #1 SMP Thu Nov 25 19:30:54 UTC 2010 i686 GNU/Linux


  • Wi-Fi chipset is Intel's 4965.
  • I reproduced this problem on 2.6.32, 2.6.36 and 2.6.37-rc4 kernel versions.
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It looks for me like kernel error (i.e. it returns errno -34) or networkmanager (i.e. it checks errno variable when it shouldn't). – Maciej Piechotka Dec 8 '10 at 11:37
@Mac I updated the log lines. I think I selected wrong ones last time. – Tshepang Dec 10 '10 at 7:19
Ok. Now it looks like hardware/firmware(microcode)/kernel error. Probably either hardware or firmware. The NM does not notice the restart - hence the error. – Maciej Piechotka Dec 11 '10 at 0:40
note: I haven't experienced this problem for weeks now, and have no idea what 'fixed' it. Nothing points to the kernel either. – Tshepang Jan 18 '11 at 20:41
note: Well, I'm experiencing it again, but less randomly. I'm back using 2.6.32. – Tshepang Feb 28 '11 at 11:50
up vote 4 down vote accepted

This is a known bug with the iwlagn driver. Updating the driver and/or firmware may fix your issue:


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