Crash with TP-Link TL-WN722N Wifi Stick

I have been trying for several days to get wireless LAN going on my BBB Rev B flashed with https://rcn-ee.net/deb/testing/2014-10-08/lxqt/BBB-eMMC-flasher-debian-jessie-lxqt-armhf-2014-10-08-2gb.img.xz. Wired networking runs without a hitch. I am using a TP-Link TL-WN722N plugged directly into the USB port.

I seem to have a kernel issue. The board has locked up a number of times doing different things - hotplugging the stick, bring the interface up with ifconfig, etc. This time I booted the board from poweroff with the stick plugged in and got a crash very early on. From dmesg:

[ 19.336926] Internal error: Oops: 5 [#1] PREEMPT SMP ARM
[ 19.342506] Modules linked in: usb_f_acm u_serial usb_f_ecm g_multi arc4 usb_f_mass_storage xt_connmark usb_f_rndis u_ether libcomposite iptable_mangle ath9k_htc ath9k_common ath9k_hw ath mac80211 cfg80211 musb_dsps musb_hdrc snd_soc_evm tda998x pvrsrvkm(O) tilcdc c_can_platform c_can drm_kms_helper can_dev snd_soc_davinci_mcasp snd_soc_edma snd_soc_omap snd_soc_hdmi_codec musb_am335x snd_soc_core snd_compress snd_pcm_dmaengine snd_pcm snd_timer snd soundcore regmap_spi mt7601Usta(O)
[ 19.387725] CPU: 0 PID: 496 Comm: ip Tainted: G O 3.14.19-ti-r28 #1
[ 19.395213] task: ddd00100 ti: dcd74000 task.ti: dcd74000
[ 19.400983] PC is at ar5008_hw_process_ini+0x2b0/0x674 [ath9k_hw]
[ 19.407383] LR is at mark_held_locks+0x70/0x15c
[ 19.412135] pc : [] lr : [] psr: 20000113
[ 19.412135] sp : dcd759e8 ip : c0d75be8 fp : 0000002d
[ 19.424173] r10: 00001378 r9 : 00000002 r8 : ddf081c0
[ 19.429650] r7 : c0c4304c r6 : 00000004 r5 : 01010201 r4 : ddf08000
[ 19.436494] r3 : 0000017d r2 : 00000000 r1 : ddd00688 r0 : 00000001
[ 19.443340] Flags: nzCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user
[ 19.450822] Control: 10c5387d Table: 9dd58019 DAC: 00000015
[ 19.456846] Process ip (pid: 496, stack limit = 0xdcd74248)
[ 19.462689] Stack: (0xdcd759e8 to 0xdcd76000)
[ 19.467261] 59e0: dcd759f8 00000002 54400000 0000017d 00020000 000013a5

[ 19.887670] [] (ar5008_hw_process_ini [ath9k_hw]) from [] (ath9k_hw_reset+0x2f0/0x1308 [ath9k_hw])
[ 19.898952] [] (ath9k_hw_reset [ath9k_hw]) from [] (ath9k_htc_start+0x90/0x1f8 [ath9k_htc])
[ 19.909766] [] (ath9k_htc_start [ath9k_htc]) from [] (ieee80211_do_open+0xa4/0xfe4 [mac80211])
[ 19.920703] [] (ieee80211_do_open [mac80211]) from [] (__dev_open+0xa8/0x10c)
[ 19.930019] [] (__dev_open) from [] (__dev_change_flags+0x94/0x154)
[ 19.938418] [] (__dev_change_flags) from [] (dev_change_flags+0x18/0x48)
[ 19.947278] [] (dev_change_flags) from [] (do_setlink+0x37c/0x870)
[ 19.955585] [] (do_setlink) from [] (rtnl_newlink+0x50c/0x600)
[ 19.963528] [] (rtnl_newlink) from [] (rtnetlink_rcv_msg+0x17c/0x21c)
[ 19.972113] [] (rtnetlink_rcv_msg) from [] (netlink_rcv_skb+0xb4/0xd8)
[ 19.980785] [] (netlink_rcv_skb) from [] (rtnetlink_rcv+0x28/0x30)
[ 19.989092] [] (rtnetlink_rcv) from [] (netlink_unicast+0xfc/0x1b8)
[ 19.997489] [] (netlink_unicast) from [] (netlink_sendmsg+0x2d0/0x6c4)
[ 20.006168] [] (netlink_sendmsg) from [] (sock_sendmsg+0x88/0xac)
[ 20.014389] [] (sock_sendmsg) from [] (___sys_sendmsg.part.28+0x2d8/0x2ec)
[ 20.023429] [] (___sys_sendmsg.part.28) from [] (__sys_sendmsg+0x4c/0x7c)
[ 20.032382] [] (__sys_sendmsg) from [] (ret_fast_syscall+0x0/0x48)
[ 20.040692] Code: e3530002 0a000001 e5973004 e12fff33 (e595360c)
[ 20.417828] —[ end trace 6a22f90d34979337 ]—

This time the board recovered and I could log in. Other times I usually get a second crash and it just locks up hard with all LEDs by the Ethernet jack on solid.

root@beaglebone:~# uname -r
3.14.19-ti-r28 (chose this flasher to get the SGX libs, but I got crashes on BBB-eMMC-flasher-debian-7.7-console-armhf-2014-10-29-2gb as well)

root@beaglebone:~# lsmod |grep ath
ath9k_htc 58125 0
ath9k_common 2686 1 ath9k_htc
ath9k_hw 405644 2 ath9k_common,ath9k_htc
ath 21532 3 ath9k_common,ath9k_htc,ath9k_hw
mac80211 479715 1 ath9k_htc
cfg80211 423777 3 ath,mac80211,ath9k_htc

I tried the “coherent_pool=2M” option in /boot/uEnv.txt from https://groups.google.com/forum/#!topic/beagleboard/Bl8wJo-245c just before this and maybe this is why I didn’t get a hard lock this time???

And I should have mentioned that I am using an Adafruit 5V 2A wall wart supply to power everything.