Comment 34 for bug 348275

This is still a problem for some users:
HW:
    description: Notebook
    product: HP Pavilion dv7 Notebook PC
    vendor: Hewlett-Packard
    version: 1
    serial: xxxxxxxxxx
    width: 64 bits
    capabilities: smbios-2.4 dmi-2.4 vsyscall64 vsyscall32

 ~$ uname -a
   2.6.28-11-generic #39-Ubuntu SMP Thu Apr 2 04:39:54 UTC 2009 x86_64 GNU/Linux

 ~$ dmesg | grep ath5k
[ 15.231457] ath5k_pci 0000:09:00.0: PCI INT A -> GSI 18 (level, low) -> IRQ 18
[ 15.231470] ath5k_pci 0000:09:00.0: setting latency timer to 64
[ 15.231558] ath5k_pci 0000:09:00.0: registered as 'phy0'
[ 15.372371] ath5k phy0: Atheros AR2425 chip found (MAC: 0xe2, PHY: 0x70)
[ 30.535823] ath5k phy0: gain calibration timeout (2412MHz)
[ 30.535827] ath5k phy0: can't reset hardware (-11)
[ 30.907197] ath5k phy0: gain calibration timeout (2412MHz)
[ 30.907202] ath5k phy0: can't reset hardware (-11)

 ~$ sudo lshw
*-network DISABLED
    description: Wireless interface
    product: AR242x 802.11abg Wireless PCI Express Adapter
    vendor: Atheros Communications Inc.
    physical id: 0
    bus info: pci@0000:09:00.0
    logical name: wmaster0
    version: 01
    serial: xx:xx:xx:xx:xx:xx
    width: 64 bits
    clock: 33MHz
    capabilities: pm msi pciexpress msix bus_master cap_list logical ethernet physical wireless
    configuration: broadcast=yes driver=ath5k_pci latency=0 module=ath5k multicast=yes wireless=IEEE 802.11bg

 ~$ iwconfig
lo no wireless extensions.

eth0 no wireless extensions.

wmaster0 no wireless extensions.

wlan0 IEEE 802.11bg ESSID:""
          Mode:Managed Frequency:2.412 GHz Access Point: Not-Associated
          Tx-Power=0 dBm
          Retry min limit:7 RTS thr:off Fragment thr=2352 B
          Power Management:off
          Link Quality:0 Signal level:0 Noise level:0
          Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
          Tx excessive retries:0 Invalid misc:0 Missed beacon:0

This used to work aprox one week ago but I am doing upgrades every day and it just broke.
It could very well been with one kernel upgrade.
My router is setup using WPA2 and works with my other Ubuntu 8.10 i686 installation on same machine.