11.04 upgrade causes ath5k driver to no longer find any wireless access points

I have an Atheros AR5414 wireless chipset in my laptop and upon upgrading from 10.10 to 11.04, the ath5k driver can no longer find any wireless networks. This problem exists in Kubuntu 11.04 and Fedora 15 Beta, which makes me think it might be an issue with the latest kernel.

Ubuntu 10.10 and prior versions worked wonderfully and it could easily find my wireless networks.

Here is some information:

root@ubuntu:/home/ubuntu# dmesg | grep ath
[ 4.188391] device-mapper: multipath: version 1.2.0 loaded
[ 4.188394] device-mapper: multipath round-robin: version 1.0.0 loaded
[ 162.870787] ath5k 0000:06:00.0: PCI INT A -> GSI 18 (level, low) -> IRQ 18
[ 162.870804] ath5k 0000:06:00.0: setting latency timer to 64
[ 162.870948] ath5k 0000:06:00.0: registered as 'phy0'
[ 163.391842] ath: EEPROM regdomain: 0x65
[ 163.391846] ath: EEPROM indicates we should expect a direct regpair map
[ 163.391850] ath: Country alpha2 being used: 00
[ 163.391852] ath: Regpair used: 0x65
[ 166.320913] ath5k phy0: Atheros AR5414 chip found (MAC: 0xa0, PHY: 0x61)

root@ubuntu:/home/ubuntu# iwconfig wlan0
wlan0 IEEE 802.11bg ESSID:off/any
          Mode:Managed Access Point: Not-Associated Tx-Power=20 dBm
          Retry long limit:7 RTS thr:off Fragment thr:off
          Encryption key:off
          Power Management:off

root@ubuntu:/home/ubuntu# iwlist wlan0 scan
wlan0 No scan results

In prior versions of Ubuntu, "iwlist wlan0 scan" would show several wireless networks.

This is my first time submitting a bug report, so if this is not enough information, please let me know.
---
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.23.
AplayDevices:
 **** List of PLAYBACK Hardware Devices ****
 card 0: Intel [HDA Intel], device 0: ALC262 Analog [ALC262 Analog]
   Subdevices: 1/1
   Subdevice #0: subdevice #0
Architecture: i386
ArecordDevices:
 **** List of CAPTURE Hardware Devices ****
 card 0: Intel [HDA Intel], device 0: ALC262 Analog [ALC262 Analog]
   Subdevices: 1/1
   Subdevice #0: subdevice #0
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: brad 1229 F.... pulseaudio
CRDA: Error: [Errno 2] No such file or directory
Card0.Amixer.info:
 Card hw:0 'Intel'/'HDA Intel at 0xdc240000 irq 44'
   Mixer name : 'Realtek ALC262'
   Components : 'HDA:10ec0262,104d1600,00100100 HDA:14f12c06,104d1700,00100000'
   Controls : 16
   Simple ctrls : 10
DistroRelease: Ubuntu 11.04
HibernationDevice: RESUME=UUID=bb3ccd38-d07e-4ac0-b6db-b6fdf842730f
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Release i386 (20110426)
Lsusb:
 Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
 Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
 Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
 Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
MachineType: Sony Corporation VGN-N365E
NonfreeKernelModules: ath_hal
Package: linux (not installed)
PccardctlIdent:
 Socket 0:
   no product info available
PccardctlStatus:
 Socket 0:
   no card
ProcEnviron:
 LANGUAGE=en_US:en
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.38-8-generic root=UUID=cef71511-b206-4fe6-bc52-13b7f2968ddb ro quiet splash vt.handoff=7
ProcVersionSignature: Ubuntu 2.6.38-8.42-generic 2.6.38.2
RelatedPackageVersions:
 linux-restricted-modules-2.6.38-8-generic N/A
 linux-backports-modules-2.6.38-8-generic N/A
 linux-firmware 1.52
RfKill:

Tags: natty running-unity
Uname: Linux 2.6.38-8-generic i686
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm admin cdrom dialout lpadmin plugdev sambashare
dmi.bios.date: 02/08/2007
dmi.bios.vendor: Phoenix Technologies LTD
dmi.bios.version: R0100J4
dmi.board.asset.tag: N/A
dmi.board.name: VAIO
dmi.board.vendor: Sony Corporation
dmi.board.version: N/A
dmi.chassis.asset.tag: N/A
dmi.chassis.type: 10
dmi.chassis.vendor: Sony Corporation
dmi.chassis.version: N/A
dmi.modalias: dmi:bvnPhoenixTechnologiesLTD:bvrR0100J4:bd02/08/2007:svnSonyCorporation:pnVGN-N365E:pvrC3LPC5A8:rvnSonyCorporation:rnVAIO:rvrN/A:cvnSonyCorporation:ct10:cvrN/A:
dmi.product.name: VGN-N365E
dmi.product.version: C3LPC5A8
dmi.sys.vendor: Sony Corporation