ar5212 won't associate until i run dhclient

On ubuntu karmic, I uninstalled network-manager and tried to configure my wireless connection manually.

iwconfig wlan0 essid MyEssid
iwconfig wlan0 txpower auto

When I run iwconfig, it says "not associated" and doesn't appear to be looking for an AP. It'll stay like this forever.

But if I run dhclient wlan0, within a few seconds it'll associate and get an address as expected.

It should find an AP and associate as soon as I give it an essid, rather than waiting until I try to send data out the interface.

ProblemType: Bug
Architecture: i386
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: jholt 1568 F.... pulseaudio
CRDA: Error: [Errno 2] No such file or directory
Card0.Amixer.info:
 Card hw:0 'I82801DBICH4'/'Intel 82801DB-ICH4 with AD1981B at irq 11'
   Mixer name : 'Analog Devices AD1981B'
   Components : 'AC97a:41445374'
   Controls : 26
   Simple ctrls : 18
Date: Mon May 17 16:41:24 2010
DistroRelease: Ubuntu 9.10
HibernationDevice: RESUME=UUID=ec93b2dd-0c7d-4b88-8b82-1891d7b00789
InstallationMedia: Ubuntu 9.10 "Karmic Koala" - Release i386 (20091028.5)
Lsusb:
 Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
 Bus 004 Device 002: ID 1668:0441 Actiontec Electronics, Inc. [hex] IBM Integrated Bluetooth II
 Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
 Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
 Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
MachineType: IBM 2373GEU
Package: linux-image-2.6.31-21-generic 2.6.31-21.59
PccardctlIdent:
 Socket 0:
   no product info available
 Socket 1:
   no product info available
PccardctlStatus:
 Socket 0:
   no card
 Socket 1:
   no card
ProcCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.31-21-generic root=UUID=79b4f802-52fc-4c68-9c8b-09fd671e65fb ro quiet splash
ProcEnviron:
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcVersionSignature: Ubuntu 2.6.31-21.59-generic
RelatedPackageVersions:
 linux-backports-modules-2.6.31-21-generic N/A
 linux-firmware 1.26
SourcePackage: linux
Uname: Linux 2.6.31-21-generic i686
dmi.bios.date: 10/13/2005
dmi.bios.vendor: IBM
dmi.bios.version: 1RETDNWW (3.19 )
dmi.board.name: 2373GEU
dmi.board.vendor: IBM
dmi.board.version: Not Available
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: IBM
dmi.chassis.version: Not Available
dmi.modalias: dmi:bvnIBM:bvr1RETDNWW(3.19):bd10/13/2005:svnIBM:pn2373GEU:pvrThinkPadT41p:rvnIBM:rn2373GEU:rvrNotAvailable:cvnIBM:ct10:cvrNotAvailable:
dmi.product.name: 2373GEU
dmi.product.version: ThinkPad T41p
dmi.sys.vendor: IBM