AP stops working?

Matt Buford matt
Fri Aug 13 06:52:24 PDT 2004

> Aug 12 15:41:33 tweeg kernel: NETDEV WATCHDOG: wifi0: transmit timed out

I have the same errors.  But are you saying yours stays down?  Mine resets
quite often and is very annoying, but it pretty much always comes back.

NICID: id=0x800c v1.0.0 (PRISM II (2.5) PCMCIA (SST parallel flash))
PRIID: id=0x0015 v1.1.1
STAID: id=0x001f v1.8.0 (station firmware)

Aug 11 10:31:52 localhost kernel: wlan0: 00:0c:85:d1:53:73 assoc_cb - STA
Aug 11 10:31:54 localhost kernel: wlan0: 00:0c:85:d1:53:73 assoc_cb - STA
Aug 11 10:36:55 localhost kernel: wlan0: sending disassociation info to STA
00:0c:85:d1:53:73(last=123432439, jiffies=123462539)
Aug 11 10:36:56 localhost kernel: wlan0: sending deauthentication info to
STA 00:0c:85:d1:53:73(last=123432439, jiffies=123462639)
Aug 11 10:37:02 localhost kernel: NETDEV WATCHDOG: wlan0: transmit timed out
Aug 11 10:37:02 localhost kernel: wlan0 Tx timed out! Resetting card
Aug 11 10:37:02 localhost kernel: wlan0: CMD=010b EVSTAT=0000 OFFSET0=0000

After months of trying to fix this, I haven't had any luck.  I've tried a
several versions of firmware with no change.

I have noticed a distinct pattern.  When transmitting a lot of data with a
weak signal and "retry" turned on, once the buffer starts filling, the card
is sure to reset quickly.  Turning off retry helps (at the expense of bad
packetloss on weak signals), however I suspect that the real issue is with a
full queue.  Turning retry off just makes a full queue a lot less likely.

If I leave things mostly idle (a little web browsing, etc) this almost never
happens.  If I fire up something like bittorrent and let it go crazy on the
uploads then the resets will occur quite regularly.  The lower my signal
quality and the more data I try to shove through the link, the more likely
it is to reset the card.

I have 4 of these Senao cards, and swapping them out doesn't cure the issue.
I've tried using them under Windows and they seemed to work fine, although
my tests there were admittedly not long enough to say for sure.

Just as a little background info, I primarily use this as a point to point
link that does not have clear line of sight, so I typically always have a
marginal signal.  I actually bounce my signal off a nearby tower.  Although
the speeds vary, the signal strength is pretty much always good enough to
work acceptably, but the card resets really make it suck.

I've also tried the Linux Orinoco driver with the same system, which doesn't
seem to suffer from this queue reset issue but it does have its own issues.
Its issues tend to be much less often (once a month or so) but they are much
more destructive.  Either the card stops working until I "iwconfig eth2 mode
ad-hoc; iwconfig eth2 mode managed" or the entire system locks up.  So, for
now I'm sticking with hostap which at least keeps on working.  Even if my
link cuts out every few minutes that beats having to travel to the office to
reset the box.

I'm running Pebble Linux on a Soekris 4521.  I've also tried ad-hoc and
master/managed modes without any improvement.

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