ath5k stops working w/ kernel oops (fails to wakeup MAC Chip)

The ath5k module fails, after which it is necessary to physically power off the hardware and then power it back on again before the wireless card works again (a simple reboot doesn't help).

uname -a:
Linux bede 2.6.27-9-generic #1 SMP Thu Nov 20 22:15:32 UTC 2008 x86_64 GNU/Linux

/proc/version_signature
Ubuntu 2.6.27-9.19-generic

[ 1237.588699] WARNING: at /build/buildd/linux-backports-modules-2.6.27-2.6.27/debian/build/build-generic/compat-wireless-2.6/net/mac80211/main.c:232 ieee80211_hw_config+0x9e/0xa0 [lbm_cw_mac80211]()
[ 1237.588706] Modules linked in: wacom af_packet i915 drm rfcomm bridge stp bnep sco l2cap bluetooth binfmt_misc ppdev ipv6 acpi_cpufreq cpufreq_userspace cpufreq_conservative cpufreq_stats cpufreq_ondemand cpufreq_powersave freq_table pci_slot wmi container sbs sbshc iptable_filter ip_tables x_tables parport_pc lp parport joydev snd_hda_intel arc4 snd_pcm_oss ecb crypto_blkcipher snd_mixer_oss snd_pcm ath5k lbm_cw_mac80211 psmouse pcspkr evdev serio_raw lbm_cw_cfg80211 snd_seq_dummy iTCO_wdt iTCO_vendor_support snd_seq_oss uvcvideo led_class snd_seq_midi snd_rawmidi snd_seq_midi_event compat_ioctl32 snd_seq videodev v4l1_compat snd_timer snd_seq_device video output snd soundcore shpchp snd_page_alloc pci_hotplug ac battery intel_agp button ext3 jbd mbcache loop sr_mod sd_mod cdrom crc_t10dif ata_generic pata_acpi sg usb_storage libusual ata_piix ahci libata scsi_mod dock r8169 ehci_hcd uhci_hcd usbcore thermal processor fan fbcon tileblit font bitblit softcursor fuse
[ 1237.588874] Pid: 2901, comm: ath5k_pci Tainted: G W 2.6.27-9-generic #1
[ 1237.588879]
[ 1237.588880] Call Trace:
[ 1237.588891] [<ffffffff8024e9b4>] warn_on_slowpath+0x64/0x90
[ 1237.588906] [<ffffffffa0319e83>] ? ath5k_hw_reset+0xa3/0x1140 [ath5k]
[ 1237.588915] [<ffffffff803a73d5>] ? __ratelimit+0xa5/0xf0
[ 1237.588921] [<ffffffff80471665>] ? net_ratelimit+0x15/0x20
[ 1237.588935] [<ffffffffa031d8d2>] ? ath5k_reset+0x232/0x240 [ath5k]
[ 1237.588959] [<ffffffffa02d597e>] ieee80211_hw_config+0x9e/0xa0 [lbm_cw_mac80211]
[ 1237.588985] [<ffffffffa02db162>] ieee80211_scan_work+0x142/0x1b0 [lbm_cw_mac80211]
[ 1237.589006] [<ffffffffa02db020>] ? ieee80211_scan_work+0x0/0x1b0 [lbm_cw_mac80211]
[ 1237.589038] [<ffffffff80262802>] run_workqueue+0xc2/0x1a0
[ 1237.589046] [<ffffffff80262b0f>] worker_thread+0xaf/0x130
[ 1237.589053] [<ffffffff80267050>] ? autoremove_wake_function+0x0/0x40
[ 1237.589061] [<ffffffff80262a60>] ? worker_thread+0x0/0x130
[ 1237.589067] [<ffffffff80266c1e>] kthread+0x4e/0x90
[ 1237.589073] [<ffffffff80213c99>] child_rip+0xa/0x11
[ 1237.589079] [<ffffffff80266bd0>] ? kthread+0x0/0x90
[ 1237.589085] [<ffffffff80213c8f>] ? child_rip+0x0/0x11
[ 1237.589089]
[ 1237.589092] ---[ end trace 3d2b9c8f919c6d4b ]---
[ 1237.626649] ath5k phy0: failed to wakeup the MAC Chip
[ 1237.626652] ath5k phy0: can't reset hardware (-5)
[ 1237.626666] ------------[ cut here ]------------