I am having the same issue. However, everything does work on startup and continues to work until calling wpa_supplicant manually or ifdown. Additionally, it can be 'fixed' by removing the driver module (I'm using b43) and re-inserting it, then running /etc/init.d/networking restart. While it is 'working', iwlist scanning returns nothing. I'm also attaching the results from running wpa_supplicant -ddd. It seems to me that it isn't necessarily an issue in WPA but in the driver (at least in my case), as it is failing to get anything from an AP scan. Hope that helps someone!
Cheers, Christopher
Initializing interface 'wlan0' conf '/etc/wpa_supplicant.conf' driver 'wext' ctrl_interface 'N/A' bridge 'N/A' Configuration file '/etc/wpa_supplicant.conf' -> '/etc/wpa_supplicant.conf' Reading configuration file '/etc/wpa_supplicant.conf' Line: 1 - start of a new network block ssid - hexdump_ascii(len=8): 53 4b 59 32 39 30 36 39 SKY29069 scan_ssid=1 (0x1) key_mgmt: 0x2 PSK (ASCII passphrase) - hexdump_ascii(len=8): [REMOVED] PSK (from passphrase) - hexdump(len=32): [REMOVED] Priority group 0 id=0 ssid='SKY29069' SIOCGIWRANGE: WE(compiled)=22 WE(source)=21 enc_capa=0xf capabilities: key_mgmt 0xf enc 0xf flags 0x0 WEXT: Operstate: linkmode=1, operstate=5 Own MAC address: 00:0c:e5:53:12:da wpa_driver_wext_set_wpa wpa_driver_wext_set_key: alg=0 key_idx=0 set_tx=0 seq_len=0 key_len=0 wpa_driver_wext_set_key: alg=0 key_idx=1 set_tx=0 seq_len=0 key_len=0 wpa_driver_wext_set_key: alg=0 key_idx=2 set_tx=0 seq_len=0 key_len=0 wpa_driver_wext_set_key: alg=0 key_idx=3 set_tx=0 seq_len=0 key_len=0 wpa_driver_wext_set_countermeasures wpa_driver_wext_set_drop_unencrypted RSN: flushing PMKID list in the driver Setting scan request: 0 sec 100000 usec WPS: UUID based on MAC address - hexdump(len=16): 7a 5a 5b ef 7b 8b 56 a3 90 25 20 26 76 fa 9f 26 WPS: Build Beacon and Probe Response IEs WPS: * Version WPS: * Wi-Fi Protected Setup State (0) WPS: * Version WPS: * Wi-Fi Protected Setup State (0) WPS: * Response Type (2) WPS: * UUID-E WPS: * Manufacturer WPS: * Model Name WPS: * Model Number WPS: * Serial Number WPS: * Primary Device Type WPS: * Device Name WPS: * Config Methods (0) WPS: * RF Bands (3) EAPOL: SUPP_PAE entering state DISCONNECTED EAPOL: KEY_RX entering state NO_KEY_RECEIVE EAPOL: SUPP_BE entering state INITIALIZE EAP: EAP entering state DISABLED Added interface wlan0 RTM_NEWLINK: operstate=0 ifi_flags=0x1003 ([UP]) RTM_NEWLINK, IFLA_IFNAME: Interface 'wlan0' added Wireless event: cmd=0x8b06 len=12 State: DISCONNECTED -> SCANNING Starting AP scan (specific SSID) Scan SSID - hexdump_ascii(len=8): 53 4b 59 32 39 30 36 39 SKY29069 Trying to get current scan results first without requesting a new scan to speed up initial association Received 0 bytes of scan results (0 BSSes) Cached scan results are empty - not posting Selecting BSS from priority group 0 Try to find WPA-enabled AP Try to find non-WPA AP No suitable AP found. Setting scan request: 0 sec 0 usec Starting AP scan (broadcast SSID) Scan requested (ret=0) - scan timeout 5 seconds RTM_NEWLINK: operstate=0 ifi_flags=0x1003 ([UP]) RTM_NEWLINK, IFLA_IFNAME: Interface 'wlan0' added Wireless event: cmd=0x8b19 len=16 Received 0 bytes of scan results (0 BSSes) CTRL-EVENT-SCAN-RESULTS Selecting BSS from priority group 0 Try to find WPA-enabled AP Try to find non-WPA AP No suitable AP found. Setting scan request: 5 sec 0 usec EAPOL: disable timer tick Starting AP scan (specific SSID) Scan SSID - hexdump_ascii(len=8): 53 4b 59 32 39 30 36 39 SKY29069 Scan requested (ret=0) - scan timeout 30 seconds RTM_NEWLINK: operstate=0 ifi_flags=0x1003 ([UP]) RTM_NEWLINK, IFLA_IFNAME: Interface 'wlan0' added Wireless event: cmd=0x8b19 len=16 Received 0 bytes of scan results (0 BSSes) CTRL-EVENT-SCAN-RESULTS Selecting BSS from priority group 0 Try to find WPA-enabled AP Try to find non-WPA AP No suitable AP found. Setting scan request: 5 sec 0 usec Starting AP scan (broadcast SSID) Scan requested (ret=0) - scan timeout 30 seconds RTM_NEWLINK: operstate=0 ifi_flags=0x1003 ([UP]) RTM_NEWLINK, IFLA_IFNAME: Interface 'wlan0' added Wireless event: cmd=0x8b19 len=16 Received 0 bytes of scan results (0 BSSes) CTRL-EVENT-SCAN-RESULTS Selecting BSS from priority group 0 Try to find WPA-enabled AP Try to find non-WPA AP No suitable AP found. Setting scan request: 5 sec 0 usec Starting AP scan (specific SSID) Scan SSID - hexdump_ascii(len=8): 53 4b 59 32 39 30 36 39 SKY29069 Scan requested (ret=0) - scan timeout 30 seconds RTM_NEWLINK: operstate=0 ifi_flags=0x1003 ([UP]) RTM_NEWLINK, IFLA_IFNAME: Interface 'wlan0' added Wireless event: cmd=0x8b19 len=16 Received 0 bytes of scan results (0 BSSes) CTRL-EVENT-SCAN-RESULTS Selecting BSS from priority group 0 Try to find WPA-enabled AP Try to find non-WPA AP No suitable AP found. Setting scan request: 5 sec 0 usec Starting AP scan (broadcast SSID) Scan requested (ret=0) - scan timeout 30 seconds RTM_NEWLINK: operstate=0 ifi_flags=0x1003 ([UP]) RTM_NEWLINK, IFLA_IFNAME: Interface 'wlan0' added Wireless event: cmd=0x8b19 len=16 Received 0 bytes of scan results (0 BSSes) CTRL-EVENT-SCAN-RESULTS Selecting BSS from priority group 0 Try to find WPA-enabled AP Try to find non-WPA AP No suitable AP found. Setting scan request: 5 sec 0 usec Starting AP scan (specific SSID) Scan SSID - hexdump_ascii(len=8): 53 4b 59 32 39 30 36 39 SKY29069 Scan requested (ret=0) - scan timeout 30 seconds RTM_NEWLINK: operstate=0 ifi_flags=0x1003 ([UP]) RTM_NEWLINK, IFLA_IFNAME: Interface 'wlan0' added Wireless event: cmd=0x8b19 len=16 Received 0 bytes of scan results (0 BSSes) CTRL-EVENT-SCAN-RESULTS Selecting BSS from priority group 0 Try to find WPA-enabled AP Try to find non-WPA AP No suitable AP found. Setting scan request: 5 sec 0 usec Starting AP scan (broadcast SSID) Scan requested (ret=0) - scan timeout 30 seconds RTM_NEWLINK: operstate=0 ifi_flags=0x1003 ([UP]) RTM_NEWLINK, IFLA_IFNAME: Interface 'wlan0' added Wireless event: cmd=0x8b19 len=16 Received 0 bytes of scan results (0 BSSes) CTRL-EVENT-SCAN-RESULTS Selecting BSS from priority group 0 Try to find WPA-enabled AP Try to find non-WPA AP No suitable AP found. Setting scan request: 5 sec 0 usec Starting AP scan (specific SSID) Scan SSID - hexdump_ascii(len=8): 53 4b 59 32 39 30 36 39 SKY29069 Scan requested (ret=0) - scan timeout 30 seconds RTM_NEWLINK: operstate=0 ifi_flags=0x1003 ([UP]) RTM_NEWLINK, IFLA_IFNAME: Interface 'wlan0' added Wireless event: cmd=0x8b19 len=16 Received 0 bytes of scan results (0 BSSes) CTRL-EVENT-SCAN-RESULTS Selecting BSS from priority group 0 Try to find WPA-enabled AP Try to find non-WPA AP No suitable AP found. Setting scan request: 5 sec 0 usec Starting AP scan (broadcast SSID) Scan requested (ret=0) - scan timeout 30 seconds RTM_NEWLINK: operstate=0 ifi_flags=0x1003 ([UP]) RTM_NEWLINK, IFLA_IFNAME: Interface 'wlan0' added Wireless event: cmd=0x8b19 len=16 Received 0 bytes of scan results (0 BSSes) CTRL-EVENT-SCAN-RESULTS Selecting BSS from priority group 0 Try to find WPA-enabled AP Try to find non-WPA AP No suitable AP found. Setting scan request: 5 sec 0 usec CTRL-EVENT-TERMINATING - signal 2 received Removing interface wlan0 State: SCANNING -> DISCONNECTED wpa_driver_wext_set_operstate: operstate 0->0 (DORMANT) WEXT: Operstate: linkmode=-1, operstate=5 No keys have been configured - skip key clearing EAPOL: External notification - portEnabled=0 EAPOL: External notification - portValid=0 wpa_driver_wext_set_wpa wpa_driver_wext_set_drop_unencrypted wpa_driver_wext_set_countermeasures No keys have been configured - skip key clearing Cancelling scan request Cancelling authentication timeout WEXT: Operstate: linkmode=0, operstate=6