Hello,
I have been following the wireless-testing branch for a few months,
hoping with each revision that my Atheros card would finally work
properly with ath5k.  So far, I've been able to scan for and see nearby
networks, but I haven't been able to associate to them.  A couple of
days ago, I was finally able to associate to a neighbor's open wireless
network, but it took several attempts and the connection only lasted for
about 5 minutes.  I have been unable to reestablish the connection using
ath5k since, but it works reliably using madwifi.
I use wpa_supplicant, and have tried versions 0.6.4, 0.6.7, and 0.6.8. 
I have tried setting my regulatory domain through both 'iw reg set US'
and adding 'country=US' to wpa_supplicant.conf.  'iw reg get' always returns
country 00:
        (2402 - 2472 @ 40), (6, 20)
        (2457 - 2482 @ 20), (6, 20), PASSIVE-SCAN, NO-IBSS
        (2474 - 2494 @ 20), (6, 20), NO-OFDM, PASSIVE-SCAN, NO-IBSS
        (5170 - 5250 @ 40), (6, 20), PASSIVE-SCAN, NO-IBSS
        (5735 - 5835 @ 40), (6, 20), PASSIVE-SCAN, NO-IBSS
I've included system information below, and have attached a copy of my
kernel .config.

Kernel Version: 2.6.29-wl-dirty from 
git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless-testing.git
with l7-filter iptables patches.
git branch: master
git describe: v2.6.29-20318-g9aa4755
kernel .config: attached

lspci:
03:00.0 Ethernet controller [0200]: Atheros Communications Inc. AR5212
802.11abg NIC [168c:1014] (rev 01)
        Subsystem: IBM ThinkPad 11a/b/g Wireless LAN Mini Express
Adapter (AR5BXB6) [1014:058a]
        Flags: bus master, fast devsel, latency 0, IRQ 11
        Memory at df2f0000 (64-bit, non-prefetchable) [size=64K]
        Capabilities: [40] Power Management version 2
        Capabilities: [50] MSI: Mask- 64bit- Count=1/1 Enable-
        Capabilities: [60] Express Legacy Endpoint, MSI 00
        Capabilities: [90] MSI-X: Enable- Mask- TabSize=1
        Capabilities: [100] Advanced Error Reporting
        Capabilities: [140] Virtual Channel <?>
        Kernel modules: ath_pci, ath5k

dmesg when loading ath_pci:
[  798.819830] AR5210, AR5211, AR5212, AR5416, RF5111, RF5112, RF2413,
RF5413, RF2133, RF2425, RF2417)
[  798.837673] ath_pci 0000:03:00.0: PCI INT A -> GSI 17 (level, low) ->
IRQ 17
[  798.837689] ath_pci 0000:03:00.0: setting latency timer to 64
[  799.387097] MadWifi: ath_attach: Switching rfkill capability on.
[  799.389648] wifi0 (ath_pci): not using net_device_ops yet
[  799.390814] wifi0: Atheros AR5424 chip found (MAC 10.3, PHY SChip
6.1, Radio 10.2)
[  799.395566] ath0 (ath_pci): not using net_device_ops yet
[  799.396500] ath_pci: wifi0: Atheros 5212: mem=0xdf2f0000, irq=17

dmesg when loading ath5k:
[  843.843981] Bridge firewalling registered
[  855.005203] ath_pci 0000:03:00.0: PCI INT A disabled
[  887.087300] ath5k 0000:03:00.0: PCI INT A -> GSI 17 (level, low) ->
IRQ 17
[  887.087329] ath5k 0000:03:00.0: setting latency timer to 64
[  887.087463] ath5k 0000:03:00.0: registered as 'phy0'
[  887.316102] phy0: Selected rate control algorithm 'minstrel'
[  887.319439] Registered led device: ath5k-phy0::rx
[  887.319459] Registered led device: ath5k-phy0::tx
[  887.319462] ath5k phy0: Atheros AR5414 chip found (MAC: 0xa3, PHY: 0x61)
[  887.467016] ADDRCONF(NETDEV_UP): wlan0: link is not ready

Thank you,

Will Keaney