wpa_supplicant AP scanning doesn't work after first association

Hi,

The station boots up and associates with the AP OK.  This works great
for days.  If I power down the AP and power it up again, after
disassociating, wpa_supplicant fails to locate the access point in its
scans.

I am using RELENG_6 from 3 September.

The station is a D-Link DWL-G510 (atheros based)
ath0_at_pci0:8:0:  class=0x020000 card=0x3a161186 chip=0x001a168c rev=0x01 hdr=0x00.

rc.conf entry:
ifconfig_ath0="WPA inet 192.168.0.1 netmask 255.255.255.0"

wpa_supplicant.conf contains:
ctrl_interface=/var/run/wpa_supplicant
ctrl_interface_group=wheel
network={
        ssid="sunset"
        scan_ssid=1
        key_mgmt=WPA-PSK
	psk= ... etc etc ...
}

The access point is a D-Link DI-524 firmware v2.02, configured for
WPA-PSK

Output from wpa_supplicant:

Starting AP scan (specific SSID)
Scan SSID - hexdump_ascii(len=6):
     73 75 6e 73 65 74                                 sunset          
Received 0 bytes of scan results (1 BSSes)
Scan results: 1
Selecting BSS from priority group 0
0: 00:0f:3d:29:79:f5 ssid='sunset' wpa_ie_len=24 rsn_ie_len=0
   selected
Trying to associate with 00:0f:3d:29:79:f5 (SSID='sunset' freq=2437 MHz)
Cancelling scan request
Automatic auth_alg selection: 0x1
WPA: using IEEE 802.11i/D3.0
WPA: Selected cipher suites: group 8 pairwise 8 key_mgmt 2
WPA: using GTK TKIP
WPA: using PTK TKIP
WPA: using KEY_MGMT WPA-PSK WPA: Own WPA IE - hexdump(len=24): dd 16 00 50 f2 01 01 00 00 50 f2 02 01 00 00 50 f2 02 01 00 00 50 f2 02
No keys have been configured - skip key clearing
wpa_driver_bsd_set_drop_unencrypted: enabled=1 
wpa_driver_bsd_associate: ssid 'sunset' wpa ie len 24 pairwise 2 group 2 key mgmt 1
wpa_driver_bsd_associate: set PRIVACY 1
Setting authentication timeout: 5 sec 0 usec
Association event - clear replay counter
Associated to a new BSS: BSSID=00:0f:3d:29:79:f5
No keys have been configured - skip key clearing
Associated with 00:0f:3d:29:79:f5
Setting authentication timeout: 10 sec 0 usec
RX EAPOL from 00:0f:3d:29:79:f5 

... power down AP, wait a minute, power up AP  ...

Starting AP scan (broadcast SSID)
Received 0 bytes of scan results (0 BSSes)
Scan results: 0
Selecting BSS from priority group 0
No suitable AP found.
Setting scan request: 5 sec 0 usec
Starting AP scan (specific SSID)
Scan SSID - hexdump_ascii(len=6):
     73 75 6e 73 65 74                                 sunset          
Received 0 bytes of scan results (0 BSSes)
Scan results: 0
Selecting BSS from priority group 0
No suitable AP found.


Please let me know what other information I can collect to help figure
this out.  I hope it's not pilot error :)

-- 
Sam Lawrance                            lawrance_at_FreeBSD.org
ph +61 0425 228 579                    boris_at_brooknet.com.au