Re: Connection problems with wme enabled

Sam Leffler <sam_at_freebsd.org> wrote:

> It would still be worth understanding why WME operation breaks iwi; 
> please provide logs showing what is happening.

Where would I get meaningful logs?

dmesg doesn't show any relevant messages,
even when booted in verbose mode.

The ifconfig output looks normal (to me) as well:

fk_at_TP51 ~ $sudo ifconfig -v wlan0
wlan0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
        ether 00:0e:...
        inet 192.168.0.49 netmask 0xffffff00 broadcast 192.168.0.255
        media: IEEE 802.11 Wireless Ethernet OFDM/54Mbps mode 11g
        status: associated
        ssid ... channel 7 (2442 Mhz 11g) bssid 00:14:...
        regdomain DEBUG country DE anywhere -ecm authmode OPEN -wps -tsn
        privacy ON deftxkey 1
        wepkey 1:104-bit powersavemode OFF powersavesleep 100 txpower 30
        txpowmax 50.0 -dotd rtsthreshold 2346 fragthreshold 2346 bmiss 24
        11b    ucast NONE    mgmt  1 Mb/s mcast  1 Mb/s maxretry 6
        11g    ucast NONE    mgmt  1 Mb/s mcast  1 Mb/s maxretry 6
        11na   ucast NONE    mgmt  0 MCS  mcast  0 MCS  maxretry 6
        11ng   ucast NONE    mgmt  0 MCS  mcast  0 MCS  maxretry 6
        scanvalid 60 -bgscan bgscanintvl 300 bgscanidle 250
        roam:11b    rssi    7dBm rate  1 Mb/s
        roam:11g    rssi    7dBm rate  5 Mb/s -pureg protmode CTS -ht
        -htcompat -ampdu ampdulimit 8k ampdudensity - -amsdu -shortgi
        htprotmode RTSCTS -puren wme -burst -ff -dturbo -dwds roaming AUTO
        bintval 100
        AC_BE cwmin  4 cwmax 10 aifs  3 txopLimit   0 -acm ack
              cwmin  4 cwmax 10 aifs  3 txopLimit   0 -acm
        AC_BK cwmin  4 cwmax 10 aifs  7 txopLimit   0 -acm ack
              cwmin  4 cwmax 10 aifs  7 txopLimit   0 -acm
        AC_VI cwmin  3 cwmax  4 aifs  2 txopLimit  94 -acm ack
              cwmin  3 cwmax  4 aifs  2 txopLimit  94 -acm
        AC_VO cwmin  2 cwmax  3 aifs  2 txopLimit  47 -acm ack
              cwmin  2 cwmax  3 aifs  2 txopLimit  47 -acm
        groups: wlan 

While it shows association, open connections stall and
I can't create new ones until reviving the device with
ifconfig wlan0 down up.

Under load (100K download rate) and with wme enabled
the problem occurs after less than 5 seconds, if there's
less load, it'll work a bit longer.

wlanstats while the device is unresponsive:

fk_at_TP51 ~ $wlanstats 
1        rx from wrong bssid
4756     rx discard 'cuz dup
33       rx discard 'cuz mcast echo
6        rx discard mgt frames
471      rx beacon frames
6        rx element unknown
390      rx frame chan mismatch
8        rx disassociation
8        beacon miss events handled
23       rx discard 'cuz port unauthorized
25       active scans started
123844   wep crypto done in s/w
934      rx management frames
24       tx failed 'cuz vap not in RUN state
165      total data frames received
160      unicast data frames received
5        multicast data frames received
355      total data frames transmit
355      unicast data frames sent
54M      current transmit rate
42       current rssi
42       current signal (dBm)

While the number of "chan mismatch" seems high,
I get the impression that it only increases while
the device is getting down and up. It doesn't seem
to increase while the device is working or hanging.

wlanstats a bit later with wme disabled and wlan0 working:

fk_at_TP51 ~ $wlanstats 
1        rx from wrong bssid
4891     rx discard 'cuz dup
33       rx discard 'cuz mcast echo
6        rx discard mgt frames
519      rx beacon frames
6        rx element unknown
453      rx frame chan mismatch
8        rx disassociation
8        beacon miss events handled
23       rx discard 'cuz port unauthorized
27       active scans started
130514   wep crypto done in s/w
1048     rx management frames
25       tx failed 'cuz vap not in RUN state
3318     total data frames received
3318     unicast data frames received
2829     total data frames transmit
2829     unicast data frames sent
36M      current transmit rate
42       current rssi
42       current signal (dBm)

It's interesting that with wme enabled the hangs
usually occur with the transmit rate at 54, while
it's usually a lot lower with wme disabled and the
device working.

Manually setting the transmit rate to a lower value
doesn't prevent the hangs though.

While the problem occurs, stuff like
"ifconfig wlan0 scan" hangs as well.

There are several access points in my neighbourhood,
mine doesn't always have the strongest signal:

fk_at_TP51 ~ $ifconfig wlan0 scan
SSID            BSSID              CHAN RATE   S:N     INT CAPS
...             00:18:...           11   54M  21:0    100 EPS 
my ap           00:14:...            7   54M  21:0    100 EPS  WME
...             00:15:...            6   54M  14:0    100 EPB  WPA
...             00:04:...            6   54M  19:0    100 EP   WPA WME

I can't reproduce the problem with ath0.

I'll be glad to provide further information, just tell me what you need.

Fabian