Re: [Ipw2100-devel] [PATCH] ipw2200: rework scan handling while associated

[Zhu Yi <yi.zhu@intel.com>]

On Wed, 2008-12-03 at 17:33 +0800, Zhu Yi wrote:
> On Mon, 2008-12-01 at 18:10 +0800, Helmut Schaa wrote:
> > That only happens while associated. Scanning while not associated
> > works like
> > a charm.
> > 
> > Here are some more informations:
> > If I load the unmodified module with debug=0x3FFF I get the following
> > log
> > when triggering a scan while associated:
> > 
> > ipw2200: U ipw_wx_set_scan Start scan
> > 00000000 03 00 00 00 0D 24 28 2C  30 34 38 3C 40 95 99 9D   .....$(,
> > 048<@...
> > 00000010 A1 A5 4A 02 03 04 05 06  07 08 09 0A 0B 00 00
> > 00   ..J..... ........
> > 00000020 00 00 00 00 00 00 00 00  00 00 00 00 00 00 00
> > 00   ........ ........
> > 00000030 00 00 00 00 00 00 00 00  00 00 03 33 31 11 13
> > 33   ........ ...31..3
> > 00000040 33 03 33 33 33 33 30 00  00 00 00 00 00 00 00 00
> > 3.33330. ........
> > 00000050 00 00 00 00 00 00 00 00  78 00 14 00 14 00 14 00   ........
> > x.......
> > martian source 255.255.255.255 from 149.44.170.156, on dev eth1
> > ll header: ff:ff:ff:ff:ff:ff:00:19:99:28:58:5b:08:00
> > ipw2200: I ipw_rx_notification type = 12 (46 bytes)
> > ipw2200: I ipw_rx_notification Scan result for channel 36
> > ipw2200: I ipw_rx_notification type = 12 (46 bytes)
> > ipw2200: I ipw_rx_notification Scan result for channel 40
> > ipw2200: I ipw_rx_notification type = 12 (46 bytes)
> > ipw2200: I ipw_rx_notification Scan result for channel 44
> > ipw2200: I ipw_rx_notification type = 25 (4 bytes)
> > ipw2200: I ipw_rx_notification type = 12 (46 bytes)
> > ipw2200: I ipw_rx_notification Scan result for channel 48
> > 
> > The channels 36-48 are active 11a channels. The next channel would be
> > 52 which
> > is a passive channel.
> > 
> > martian source 255.255.255.255 from 149.44.170.66, on dev eth1
> > ll header: ff:ff:ff:ff:ff:ff:00:0e:0c:aa:5c:c5:08:00
> > ipw2200: I ipw_rx_notification type = 25 (4 bytes)
> > ipw2200: I ipw_rx_notification type = 25 (4 bytes)
> > ipw2200: I ipw_rx_notification type = 25 (4 bytes)
> > ipw2200: I ipw_rx_notification type = 25 (4 bytes)
> > ipw2200: I ipw_rx_notification type = 25 (4 bytes)
> > ipw2200: I ipw_rx_notification type = 25 (4 bytes)
> > ipw2200: I ipw_rx_notification type = 17 (8 bytes)
> > ipw2200: I ipw_handle_missed_beacon Aborting scan with missed beacon.
> > ipw2200: I ipw_handle_missed_beacon Missed beacon: 1
> > 
> > Aha, the firmware noticed a beacon miss before the scan watchdog
> > restarts the firmware (the log is without timestamps, sorry).
> > 
> > ipw2200: I ipw_rx_notification type = 13 (4 bytes)
> > ipw2200: I ipw_rx_notification Scan completed: type 1, 5 channels, 2
> > status
> > 
> > Status 2 -> Scan aborted.
> 
> We will look at this.

Sorry for the late reply.

We look at the firmware. If the dwell time is set longer than the time
remaining for firmware to switch back before DTIM TBTT, the firmware
will discard this request without feeding back any notifications. So if
we set passive dwell to 120, it is possible the scan request is ignored
by firmware (assume beacon interval is 100, DTIM for every other
beacon). But the firmware is not stuck in this case, it just won't send
us scan notifications any more.

So your patch is correct. Can you please remove the scan watchdog part
and resend it?

Thanks,
-yi