debian, iwlwifi : rfkill seems to halt wifi connection periodically

Question

[Context]

I'am installing a Debian on my new computer : uname -a is Linux myname 3.2.0-4-amd64 #1 SMP Debian 3.2.57-3+deb7u1 x86_64 GNU/Linux.

I'am trying to use my wifi, lspci gives 02:00.0 Network controller: Intel Corporation Centrino Wireless-N 135 (rev c4). The non-free package iwlwifi is installed and iwlwifi-135-6.ucode is in /lib/firmware. My version is 18.168.6.1, as http://wireless.kernel.org/en/users/Drivers/iwlwifi

The network manager manages to see networks for a few seconds, try to connect, then disconnect, then make attempt to connect again...Here are abstracts of dmesg :

 [  244.217533] iwlwifi 0000:02:00.0: RF_KILL bit toggled to enable radio.
 [  245.222313] iwlwifi 0000:02:00.0: RF_KILL bit toggled to enable radio.
 [  246.226945] iwlwifi 0000:02:00.0: RF_KILL bit toggled to enable radio.
 [  247.231622] iwlwifi 0000:02:00.0: RF_KILL bit toggled to enable radio.
 [  248.236492] iwlwifi 0000:02:00.0: RF_KILL bit toggled to enable radio.
 [  249.240733] iwlwifi 0000:02:00.0: RF_KILL bit toggled to enable radio.
 [  250.245314] iwlwifi 0000:02:00.0: RF_KILL bit toggled to enable radio.
 [  251.249968] iwlwifi 0000:02:00.0: RF_KILL bit toggled to enable radio.
 [  252.254369] iwlwifi 0000:02:00.0: RF_KILL bit toggled to enable radio.

[Attempts]

If i type sudo modprobe -r iwlwifi ;sudo modprobe -a iwlwifi , i get (in dmesg ) :

 ...
 [ 1613.133381] ADDRCONF(NETDEV_UP): wlan0: link is not ready
 [ 1613.764081] wlan0: authenticate with 42:42:42:42:42:42 (try 1) //it's not 42:42:42:42:42:42...
 [ 1613.766123] wlan0: authenticated
 [ 1613.768241] wlan0: associate with 42:42:42:42:42:42 (try 1)
 [ 1613.777522] wlan0: RX ReassocResp from 42:42:42:42:42:42 (capab=0x411 status=0 aid=2)
 [ 1613.777532] wlan0: associated
 [ 1613.784776] ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready
 [ 1613.909236] iwlwifi 0000:02:00.0: RF_KILL bit toggled to enable radio.
 [ 1614.913201] iwlwifi 0000:02:00.0: RF_KILL bit toggled to enable radio.
 [ 1615.917653] iwlwifi 0000:02:00.0: RF_KILL bit toggled to enable radio.
 [ 1615.917758] iwlwifi 0000:02:00.0: Not sending command - RF KILL
 [ 1615.917765] iwlwifi 0000:02:00.0: Error sending REPLY_RXON_ASSOC: enqueue_hcmd failed: -5
 [ 1615.917775] iwlwifi 0000:02:00.0: Error setting RXON_ASSOC (-5)
 [ 1615.917908] iwlwifi 0000:02:00.0: Not sending command - RF KILL
 [ 1615.917916] iwlwifi 0000:02:00.0: Error sending REPLY_QOS_PARAM: enqueue_hcmd failed: -5
 [ 1615.917923] iwlwifi 0000:02:00.0: Failed to update QoS
 [ 1615.917932] iwlwifi 0000:02:00.0: Not sending command - RF KILL
 [ 1615.917937] iwlwifi 0000:02:00.0: Error sending REPLY_RXON: enqueue_hcmd failed: -5
 [ 1615.917943] iwlwifi 0000:02:00.0: Error clearing ASSOC_MSK on BSS (-5)
 [ 1615.917958] iwlwifi 0000:02:00.0: Not sending command - RF KILL
 [ 1615.917964] iwlwifi 0000:02:00.0: Error sending REPLY_RXON: enqueue_hcmd failed: -5
 [ 1615.917971] iwlwifi 0000:02:00.0: Error clearing ASSOC_MSK on BSS (-5)
 [ 1615.917980] iwlwifi 0000:02:00.0: Not sending command - RF KILL
 [ 1615.917987] iwlwifi 0000:02:00.0: Error sending REPLY_RXON: enqueue_hcmd failed: -5
 [ 1615.917994] iwlwifi 0000:02:00.0: Error clearing ASSOC_MSK on BSS (-5)
 [ 1615.918003] wlan0: deauthenticating from 42:42:42:42:42:42 by local choice (reason=3)
 [ 1615.927619] iwlwifi 0000:02:00.0: Attempting to modify non-existing station 0
 [ 1615.927645] iwlwifi 0000:02:00.0: iwl_send_add_sta - error in the CMD response -5
 [ 1615.927656] ieee80211 phy0: failed to remove key (1, ff:ff:ff:ff:ff:ff) from hardware (-5)
 [ 1615.947571] iwlwifi 0000:02:00.0: Attempting to modify non-existing station 0
 [ 1615.947584] iwlwifi 0000:02:00.0: iwl_send_add_sta - error in the CMD response -5
 [ 1615.947589] ieee80211 phy0: failed to remove key (0, 42:42:42:42:42:42) from hardware (-5)
 [ 1615.947653] iwlwifi 0000:02:00.0: REPLY_REMOVE_STA failed
 [ 1615.947656] iwlwifi 0000:02:00.0: Error removing station 42:42:42:42:42:42
 [ 1615.964802] cfg80211: Calling CRDA to update world regulatory domain
 [ 1616.001528] cfg80211: World regulatory domain updated:
 [ 1616.001537] cfg80211:     (start_freq - end_freq @ bandwidth), (max_antenna_gain, max_eirp)
 [ 1616.001545] cfg80211:     (2402000 KHz - 2472000 KHz @ 40000 KHz), (300 mBi, 2000 mBm)
 [ 1616.001552] cfg80211:     (2457000 KHz - 2482000 KHz @ 20000 KHz), (300 mBi, 2000 mBm)
 [ 1616.001557] cfg80211:     (2474000 KHz - 2494000 KHz @ 20000 KHz), (300 mBi, 2000 mBm)
 [ 1616.001563] cfg80211:     (5170000 KHz - 5250000 KHz @ 40000 KHz), (300 mBi, 2000 mBm)
 [ 1616.001569] cfg80211:     (5735000 KHz - 5835000 KHz @ 40000 KHz), (300 mBi, 2000 mBm)
 [ 1616.002254] iwlwifi 0000:02:00.0: L1 Disabled; Enabling L0S
 [ 1616.009919] iwlwifi 0000:02:00.0: Radio type=0x0-0x0-0x0
 [ 1616.153051] ADDRCONF(NETDEV_UP): wlan0: link is not ready
 ...(repeating many times)

Since the problem seems to come from rfkill, i tried things like sudo rfkill unblock all . However, whenever i type sudo rfkill list all, i get :

 1: hci0: Bluetooth
Soft blocked: no
Hard blocked: no
 3: phy0: Wireless LAN
Soft blocked: no
Hard blocked: no

It seems that hardware switches are fine... I also monitored the events of rfkill (sudo rfkill event), and here is what i got :

     1400772407.995946: idx 3 type 1 op 2 soft 0 hard 0
     1400772410.003509: idx 3 type 1 op 2 soft 0 hard 1
     1400772410.004361: idx 3 type 1 op 2 soft 0 hard 0
     1400772412.012073: idx 3 type 1 op 2 soft 0 hard 1
     1400772412.013314: idx 3 type 1 op 2 soft 0 hard 0

Switching of rfkill only happens when attemps to connect are performed.

It could be a problem related to airplane mode, but the light on my computer is off. I tried to push fn+f11 to switch it on and the light never turned on... I can't see any mechanical switch or fn+.. related to wifi on my computer. People facing trouble related to airplane mode seems to solve this by booting ubuntu 10.10...Would installing a debian squeeze or an Ubuntu solve this issue ?

[question]

Here are my questions :

• does it seem like an hardware problem ? Is a flame-thrower the right tool to solve this issue ?

• How do i find what is blocking rfkill from time to time ? May the firmware be the origin of this problem ?

• what would you try ? What can i try ?

Any advice would be helpful !

Answer 1

I am answering to my own question because others may have the same trouble, and i have a solution to suggest...It worked for me, so...

I did not fully understand my problem, but in the end, i downloaded ubuntu 14.04 LTS, http://www.ubuntu.com/download/desktop i copied the image on a usb bar.

I booted on the usb bar. A chose between trial and install was prompted. I chose trial. In the trail version, i managed to connect my wifi in less than 3 minutes...I switched off ubuntu and restarted debian. The problem was solved !

I am writting this through my wireless connection. I guess i will keep two usb bar by my side : one for a strong debian, and another for a great ubuntu !