Re: [linux-usb-devel] [2.6.12-rc4] network wlan connection goes down

[Colin Leroy <colin@colino.net>]

On Tue, 10 May 2005 07:07:13 -0700
David Brownell <david-b@pacbell.net> wrote:

Hi David,

> Hmm, well nothing looks wrong at the OHCI level.  It's possible that
> the data toggle got screwed up somehow; there are devices where the
> hardware doesn't reset it when it should.  If that's the case, there'd
> likely be some rx or tx error (does "ifconfig" show any?  dmesg?) and
> the wlan driver's recovery would need updating to ensure that the
> various endpoints get properly reset given those quirks.

ifconfig and dmesg don't show anything. However, the latest news is
that I rebooted (to 2.6.12-rc4 too), and it didn't reproduce. After a
few hours (plenty enough of time to get this bug), I tried to sleep and
resume the laptop a few times, I'll see if it bugs again now. Maybe
that's sleep related; as you say the usb layer looks fine...

> If you can report what the "iwconfig essid ..." command does down
> at the USB level, that should help sort things out. 

basically my iwconfig command looks like
    iwconfig mode managed essid AP channel 11 key restricted aa:bb:cc...

this results in calls to zd1201_set_mode(), zd1201_set_essid(),
zd1201_set_freq(), zd1201_set_encode() (Once each, in this order). Each
of those, at the USB level, does some register reading/writing
(zd1201_setconfig16(), zd1201_getconfig16() and friends) and at the
end, calls zd1201_mac_reset(zd), which disables and reenables the chip
using some zd1201 commands sent down an urb.
I guess this zd1201_mac_reset() call is what "fixes" it.

> It's possible that the network TX timeout mechanism might be a good
> place to kick in some driver recovery scheme. 

There's a tx_timeout callback, but it does log to dmesg and none of
these lines appear.

But I think that the problem probably lies in a complex interaction of
sleep code and usb code, and simply finding a way to reset the
zd1201 chip when it misbehaves, instead of finding the root cause,
isn't the solution. In other words, I'll get a hard time finding this
solution :)

Thanks,
-- 
Colin