Debian testing wpa_supplicant 1.03 cannot roam between wifi APs without me killing wpa_supplicant (intel 6300 AGN)

[Dan Williams]

On Tue, 2013-02-19 at 09:44 -0800, Marc MERLIN wrote:
> On Tue, Feb 19, 2013 at 04:33:45PM +0100, Holger Schurig wrote:
> > Does on "iw scan" (or wpa_cli scan) instead of killing also help?
>  
> No, it does not.
> wpa_supplicant properly notices the closer AP and switches to it. After
> that, some packets go through, and then everything stops.
> 
> If you go re-read my original message (or I can resend if you wish), the
> logs show that roaming happens ok, but just after roaming things break.
> 
> Somehow wpa_supplicant then notices that the closeby AP isn't working
> (it is, but as far as it's concerned, it's not), and forces a
> reconnection to the very far away AP.
> 
> In other words, roaming seems to work, but changing APs seems to wedge the 
> wifi chip.
> 
> > Did you try the bg_scan feature?
> 
> I'll admit to not knowing how to use this, but my problem doesn't seem
> to be lack of roaming, but that wireless networking breaks soon after
> wpa_supplicant roams.
> 
> Because everything fixes itself if I kill wpa_supplicant, I would first
> tend to think it's at fault.
> 
> But then an interesting thing happens:
> Once I get wireless wedged by having roamed to the new AP, I switch from
> magicnet-a to magicnet manually using nm-applet.
> The connection happens, but wireless is still broken:
> NetworkManager[19347]: <info> Policy set 'magicnet' (wlan0) as default for IPv4 routing and DNS.
> NetworkManager[19347]: <info> Activation (wlan0) successful, device activated.
> NetworkManager[19347]: <info> Activation (wlan0) Stage 5 of 5 (IP Configure Commit) complete.
> kernel: [52779.305375] iwlwifi 0000:03:00.0: fail to flush all tx fifo queues
> kernel: [52781.308225] iwlwifi 0000:03:00.0: fail to flush all tx fifo queues

You've got a driver problem then, not a supplicant problem.  The
driver/chip is basically dead.  You can potentially resurrect by "rmmod
iwlwifi; modprobe iwlwifi", but if you ever need to do that, the driver
is buggy.

Dan

> Then, I tried to roam back to magicnet-a, the connection succeeds, but I still
> don't get traffic to go through.
> 
> I'm going to assume that these messages are not a problem, even if I don't know their source:
> kernel: [52900.247067] Loading kernel module for a network device with CAP_SYS_MODULE (deprecated).  Use CAP_NET_ADMIN and alias netdev-tun instead.
> 
> Mmmh, in the past, I was able to just kill wpa_supplicant and it would recover
> but now that I'm using 
> /sbin/wpa_supplicant -u -onl80211
> it seems that I actually have to unload the iwlagn driver and reload it to recover.
> 
> I'm almost starting to wonder if somehow intel's wireless driver is actually at
> fault, but I'll admit to not knowing the APIs and line between wpa_supplicant
> and iwlagn.
> Also, if iwlagn was unable to roam between APs, surely it ought to be broken for many others.
> 
> Kernel is 3.7.8, but it's been like this for the entire 3.x series and
> since I got this lenovo T530 laptop AFAIK.
> 
> What do you think?
> 
> Thanks,
> Marc