Re: [gentoo-user] Atheros WLAN loosing link

[Mick]

On Sunday 27 June 2010 06:55:31 Nagatoro wrote:
> On Saturday 26 June 2010 14.35.28 Mick wrote:
> > On Friday 25 June 2010 18:52:18 Enrico Weigelt wrote:
> > > Hi folks,
> > >
> > >
> > > my Atheros wlan (builtin, internal intenna) is regularily
> > > loosing link. Reproducible in various different networks.
> > > At home, my wlan ap is about 2 meter away (within the room),
> > > so link quality (currently 53) shouldnt be the problem.
> > >
> > > Does anyone know what could cause the problem ?
> > >
> > > # cat /proc/version
> > >
> > > Linux version 2.6.31-gentoo-r10 (root@×××××××××.local) \
> > > (gcc version 4.3.4 (Gentoo 4.3.4 p1.0, pie-10.1.5) ) 	\
> > > #1 SMP Wed Jun 2 00:51:13 CEST 2010
> > >
> > > # lspci -v
> > > ...
> > >
> > > 02:00.0 Network controller: Atheros Communications Inc. AR9285 Wireless
> > > Network Adapter (PCI-Express) (rev 01) Subsystem: Askey Computer Corp.
> > > Device 7167
> > >
> > >     Flags: bus master, fast devsel, latency 0, IRQ 16
> > >     Memory at f6000000 (64-bit, non-prefetchable) [size=64K]
> > >     Capabilities: [40] Power Management version 3
> > >     Capabilities: [50] MSI: Enable- Count=1/1 Maskable- 64bit-
> > >     Capabilities: [60] Express Legacy Endpoint, MSI 00
> > >     Capabilities: [100] Advanced Error Reporting
> > >     Capabilities: [140] Virtual Channel <?>
> > >     Capabilities: [160] Device Serial Number 00-15-17-ff-ff-24-14-12
> > >     Capabilities: [170] Power Budgeting <?>
> > >     Kernel driver in use: ath9k
> > >     Kernel modules: ath9k
> > >
> > > ...
> > >
> > >
> > > Jun 25 19:36:51 excalibur kernel: wlan0: no probe response from AP
> > > 00:23:08:86:d6:8f - disassociating Jun 25 19:36:51 excalibur
> > > dhcpcd[10182]: wlan0: carrier lost
> >
> > I have seen the same problem with my internal broadcom card and of course
> > a different driver.  If you check google there seem to be pages and
> > pages of users reporting such a problem on different distros and with
> > different makes of wireless cards.
> >
> > The jury's out as to what's causing this.  Is it related to modern cards
> > with low power management capabilities and how this may interact with the
> > kernel, or is it something to do with the tolerance built into TTL
> > packets between the card and the AP?
> >
> > With regards to my card I have noticed that at home I stay connected for
> > hours on end, at work it's a miracle if I stay online for longer than 5
> > minutes (both on the same channel).  This to me says that the problem is
> > one of interaction with the router, which points to tolerance on the TTL
> > packets.
> >
> > Of course YMMV ...
>
> Last time I had this problem I tracked it to a conflict between
> wpa_supplicant and the card driver. Basicly the card driver would send a
> request to assosiate with mac 00:00:....:00 each time a new card was found
> on the air and wpa_supplicatnt interpreted this as a request from the
> driver to drop the connection. The driver folks said that this request
> should be ignored and the wpa_supplicant folks said that this should not
> be ignored but instead was a disconnect request. Catch 22...
>
> Because of this I had to use wep instead of wpa(2) for along time.

I seem to recall this as a problem too, although not in my case.  At work 
there is no encryption and despite this the connection keeps dropping, while 
at home I use WPA2.
-- 
Regards,
Mick