iwl4965 unstable on Dell XPS M1330

I can confirm this on an Asus G1S. I have to take exactly the same steps to resurrect the Internet connection.

I also get the symptom that when the connection goes down, an "iwlist scan" hangs for a few seconds, and then responds with the error "resource temporarily unavailable." Furthermore, an "iwconfig wlan0 essid <name>" has no effect and does not show the access point as associated on a subsequent "iwconfig"

This problem does not occur on every wireless network - the frequency of the problem seems to be highly dependent on how many networks are available, and on the particular make and model of the AP's hardware. I have been able to run a flawless connection for five hours on some networks, and on others I barely can stay connected for five minutes.

I can say, though, that running NetworkManager increases the likelihood of this happening. Any ideas on how we might be able to make progress toward identifying what exactly goes wrong?

Second confirmation:
it's working perfectly with some AP, not with others.

I don't think it's related to the encryption, I tried to change to different WPA settings, and it's the same.

Just to clarify, whether the AP uses WPA or is open has, to date, had no bearing on how stable my connections have been.

I also see the" REPLY_ADD_STA failed" messages in the log, but these occur even when a connection is stable.

My most recent problems have been occurring in an environment with multiple cells on the same network. I am not moving around, but still see reassociation messages in the log, FWIW.

[ 438.667303] wlan0: associated
[ 438.674065] wlan0: WMM queue=2 aci=0 acm=0 aifs=3 cWmin=15 cWmax=1023 burst=0
[ 438.674073] wlan0: WMM queue=3 aci=1 acm=0 aifs=7 cWmin=15 cWmax=1023 burst=0
[ 438.674080] wlan0: WMM queue=1 aci=2 acm=0 aifs=2 cWmin=7 cWmax=15 burst=30
[ 438.674086] wlan0: WMM queue=0 aci=3 acm=0 aifs=2 cWmin=3 cWmax=7 burst=15
[ 438.708449] iwl4965: REPLY_ADD_STA failed
[ 438.715456] wlan0: Initial auth_alg=0
[ 438.715466] wlan0: authenticate with AP 00:14:7c:01:20:00
[ 438.715486] wlan0: Initial auth_alg=0
[ 438.715490] wlan0: authenticate with AP 00:14:7c:01:20:00
[ 438.716494] wlan0: RX authentication from 00:14:7c:01:20:00 (alg=0 transaction=2 status=0)
[ 438.716502] wlan0: authenticated
[ 438.716508] wlan0: associate with AP 00:14:7c:01:20:00
[ 438.718643] wlan0: authentication frame received from 00:14:7c:01:20:00, but not in authenticate state - ignored
[ 438.721457] wlan0: RX ReassocResp from 00:14:7c:01:20:00 (capab=0x421 status=0 aid=1)
[ 438.721465] wlan0: associated
[ 438.721560] wlan0: WMM queue=2 aci=0 acm=0 aifs=3 cWmin=15 cWmax=1023 burst=0
[ 438.721568] wlan0: WMM queue=3 aci=1 acm=0 aifs=7 cWmin=15 cWmax=1023 burst=0
[ 438.721574] wlan0: WMM queue=1 aci=2 acm=0 aifs=2 cWmin=7 cWmax=15 burst=30
[ 438.721581] wlan0: WMM queue=0 aci=3 acm=0 aifs=2 cWmin=3 cWmax=7 burst=15

The latest gutsy kernel packages solved at least some of these problems for me. On a first glance, the REPLY_ADD_STA messages are gone, and one particular wireless router, which hitherto had given me a lot of problems, now works flawlessly.

Update iwlwifi to 1.1.0.

I had been seeing similar problems (REPLY_ADD_STA failed); they seem to have gone away with 1.1.0, but I'm seeing a similar result (no traffic passed) with different messages. I've filed this as bug 144621.

Possible fix:

Create the file /etc/modprobe.d/iwl4965:

----
options iwl4965 disable_hw_scan=1
----

Working much better after Gutsy updates. However sometimes it's disconnecting and no way to bring it back, except by reloading the module again. Error message in logs is different though, I will copy paste it here once I try Gutsy again.