kern/177465: 20%-100% packet loss with iwn driver

[Yakov Galka]

>Number:         177465
>Category:       kern
>Synopsis:       20%-100% packet loss with iwn driver
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Fri Mar 29 09:20:00 UTC 2013
>Closed-Date:
>Last-Modified:
>Originator:     Yakov Galka
>Release:        9.1-RELEASE
>Organization:
>Environment:
FreeBSD orthanc 9.1-RELEASE FreeBSD 9.1-RELEASE #0 r243825: Tue Dec  4 09:23:10 UTC 2012     root at farrell.cse.buffalo.edu:/usr/obj/usr/src/sys/GENERIC  amd64

>Description:
Dell Latitude E6530 with Intel Centrino Advanced-N 6205, connecting to an unencrypted access point 3m away. Pinging the access point gives 20% to 100% packet loss, 8 out of 10 days I tried. The access point is an Edimax router with 802.11n support.

Loading Ubuntu LiveCD at the same conditions gives 0% packet loss, always.

Some report similar problems, see replies to http://forums.freebsd.org/showthread.php?t=38685

>How-To-Repeat:
$ dmesg | grep -E "wlan|iwn"
module iwn already present!
iwn0: <Intel Centrino Advanced-N 6205> mem 0xf7600000-0xf7601fff irq 17 at device 0.0 on pci3
wlan0: Ethernet address: xx:xx:xx:xx:xx:xx

$ grep -E "wlan|iwn" /boot/loader.conf
if_iwn_load="YES"
iwn4965fw_load="YES"
iwn1000fw_load="YES"
iwn5000fw_load="YES"
iwn5150fw_load="YES"
iwn6000fw_load="YES"
iwn6000g2afw_load="YES"
iwn6000g2bfw_load="YES"
iwn6050fw_load="YES"
wlan_wep_load="YES"
wlan_ccmp_load="YES"
wlan_tkip_load="YES"

$ grep -E "wlan|iwn" /etc/rc.conf
wlans_iwn0="wlan0"
ifconfig_wlan0="DHCP"

$ kldstat
Id Refs Address            Size     Name
 1   34 0xffffffff80200000 1323388  kernel
 3    1 0xffffffff81549000 c6d2f0   nvidia.ko
 4    2 0xffffffff821b7000 484f8    linux.ko
 5    1 0xffffffff82200000 2ed08    iwn4965fw.ko
 6    1 0xffffffff8222f000 53520    iwn1000fw.ko
 7    1 0xffffffff82283000 54188    iwn5000fw.ko
 8    1 0xffffffff822d8000 534a8    iwn5150fw.ko
 9    1 0xffffffff8232c000 6fe80    iwn6000fw.ko
10    1 0xffffffff8239c000 6d5c8    iwn6000g2afw.ko
11    1 0xffffffff8240a000 71758    iwn6000g2bfw.ko
12    1 0xffffffff8247c000 739d0    iwn6050fw.ko

$ ifconfig iwn0 && ifconfig wlan0
iwn0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 2290
        ether xx:xx:xx:xx:xx:xx
        nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL>
        media: IEEE 802.11 Wireless Ethernet autoselect mode 11ng
        status: associated
wlan0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
        ether xx:xx:xx:xx:xx:xx
        inet 192.168.2.103 netmask 0xffffff00 broadcast 192.168.2.255
        nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL>
        media: IEEE 802.11 Wireless Ethernet DS/1Mbps mode 11ng
        status: associated
        ssid Palantir channel 13 (2472 MHz 11g ht/20) bssid xx:xx:xx:xx:xx:xx
        country US authmode OPEN privacy OFF txpower 13 bmiss 10 scanvalid 60
        bgscan bgscanintvl 300 bgscanidle 250 roam:rssi 7 roam:rate 64
        protmode CTS ampdulimit 32k ampdudensity 8 -amsdutx amsdurx shortgi
        wme

$ ping 192.168.2.1
[...]
1076 packets transmitted, 30 packets received, 97.2% packet loss
round-trip min/avg/max/stddev = 1.356/104.635/2008.506/396.671 ms

>Fix:


>Release-Note:
>Audit-Trail:
>Unformatted: