Atheros 9285 and low signal level

[Eugene Dzhurinsky]

Hello!

I recently get ASUS K43SJ laptop with Atheros wireless card, which is
recognized as:

>dmesg | grep ath
ath0: <Atheros 9285> mem 0xde600000-0xde60ffff irq 17 at device 0.0 on pci3
ath0: [ITHREAD]
ath0: AR9285 mac 192.2 RF5133 phy 14.0

>pciconf -lv:

ath0 at pci0:3:0:0:    class=0x028000 card=0x2c371a3b chip=0x002b168c rev=0x01 hdr=0x00
    vendor     = 'Atheros Communications Inc.'
    device     = 'Atheros AR9285 Wireless LAN 802.11 a/b/g/n Controller (AR928x)'
    class      = network


> ifconfig wlan1

wlan1: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
	ether 74:2f:68:ad:a4:34
	inet 192.168.1.103 netmask 0xffffff00 broadcast 192.168.1.255
	media: IEEE 802.11 Wireless Ethernet DS/11Mbps mode 11g
	status: associated
	ssid bofhe channel 6 (2437 MHz 11g) bssid 1c:af:f7:9b:59:0c
	regdomain 96 indoor ecm authmode WPA2/802.11i privacy ON
	deftxkey UNDEF TKIP 2:128-bit TKIP 3:128-bit txpower 20 bmiss 7
	scanvalid 450 bgscan bgscanintvl 300 bgscanidle 250 roam:rssi 7
	roam:rate 5 protmode CTS wme burst roaming MANUAL

>uname -a:

FreeBSD devbox 8.2-STABLE FreeBSD 8.2-STABLE #4: Wed Oct 19 00:40:20 EEST 2011 root at devbox:/usr/obj/usr/src/sys/BOFHMOD  amd64

The problem with the card is that it loses the connection with AP when it's
relatively far from it (like 5 meters), and gets it back again when laptop
gets closer to AP. I tried with SONY VAIO laptop - and it easily reports good
signal level while ASUS losts it's connection.

Additionally, airodump-ng shows only 2 access points around if started at ASUS
laptop, but on another host it shows much more stations.

So I assume something is wrong with the card on ASUS laptop, how can I debug
problems?

I tried to set:

> wlandebug -i wlan1 +xrate+assoc+auth+scan

and watched output:

Oct 19 08:54:50 devbox kernel: wlan1: scan set 6g dwell min 20ms max 200ms
Oct 19 08:54:50 devbox kernel: wlan1: scan_task: chan   6g ->   6g [active, dwell min 20ms max 200ms]
Oct 19 08:54:51 devbox kernel: wlan1: sta_pick_bss: no scan candidate
Oct 19 08:54:51 devbox kernel: wlan1: scan_task: done, [ticks 401164, dwell min 20 scanend 2147884610]
Oct 19 08:54:51 devbox kernel: wlan1: notify scan done
Oct 19 08:54:56 devbox kernel: wlan1: ieee80211_ioctl_scanreq: flags 0x20052 duration 0x7fffffff mindwell 0 maxdwell 0 nssid 1
Oct 19 08:54:56 devbox kernel: wlan1: ieee80211_check_scan: active scan, append, nojoin, once
Oct 19 08:54:56 devbox kernel: wlan1: sta_pick_bss: no scan candidate
Oct 19 08:54:56 devbox kernel: wlan1: start_scan_locked: active scan, duration 2147483647 mindwell 0 maxdwell 0, desired mode auto, append, nojoin, once

Can somebody please advice how to debug and fix the problem? Thank you in
advance!

-- 
Eugene N Dzhurinsky