DHCP does not work anymore with kernel 3.4.2+ for ath9k-WLAN-USB

tequa · 2012-06-23 10:09:42

Hello,

although i seem to be the only one to have this problem, i cannot connect to a WLAN via my TP-LINK TL-WN722N Adapter since Kernel 3.4.2 (also 3.4.3, but i did not test 3.4 or 3.4.1).
Downgrading to 3.3.8...

ok, so here, what i am usually using:

- WLAN-USB-Adaptor from TP-Link with ath9k_htc module
- Netcfg for wpa2-protected wlan

ok, so here the some information and what i tried so far:

- (as already mentioned) downgrading only the kernel to 3.3.8 makes everything work fine
- wlan at my notebook (iwlagn) works with the 3.4.2 and 3.4.3 kernel
- the TP-Link-Adaptor at my notebook does not work with 3.4.2/3-kernel (same problem with getting an ip via dhcp)
- connecting with the adaptor via wpa_supplicant works (also with 3.4.2/3), but ...
- ... then getting an ip-address with dhcpcd or dhclient times out
- netcfg with static ip seems to work, but is not really what i want (and although it's a temporary solution, there still has to be some bug or mistake somewhere)
- (and i also tried the tip from the wiki with 'iwconfig wlan0 power off')

And here some info about my system:

> lsmod | grep ath
ath9k_htc              57868  0 
ath9k_common            2096  1 ath9k_htc
ath9k_hw              342134  2 ath9k_common,ath9k_htc
ath                    15361  3 ath9k_common,ath9k_htc,ath9k_hw
mac80211              395680  1 ath9k_htc
cfg80211              170074  3 ath,mac80211,ath9k_htc
usbcore               147533  6 ohci_hcd,ehci_hcd,usbhid,ath9k_htc,xhci_hcd

> dmesg | grep ath
[    3.802152] usb 1-4: ath9k_htc: Firmware htc_9271.fw requested
[    3.802204] usbcore: registered new interface driver ath9k_htc
[    4.085059] usb 1-4: ath9k_htc: Transferred FW: htc_9271.fw, size: 51272
[    4.320541] ath9k_htc 1-4:1.0: ath9k_htc: HTC initialized with 33 credits
[    4.538384] ath9k_htc 1-4:1.0: ath9k_htc: FW Version: 1.3
[    4.538392] ath: EEPROM regdomain: 0x809c
[    4.538397] ath: EEPROM indicates we should expect a country code
[    4.538402] ath: doing EEPROM country->regdmn map search
[    4.538407] ath: country maps to regdmn code: 0x52
[    4.538411] ath: Country alpha2 being used: CN
[    4.538415] ath: Regpair used: 0x52
[    4.546170] Registered led device: ath9k_htc-phy0

any hints?

thank you in advance

tequa · 2012-06-23 11:17:36

Hm, i just found out something perhaps helpful...

i tried to run wireshark while trying 'dhcpcd wlan0' ... and dhcp worked... i was happy, tried again without wireshark - and it did not work... i wondered ... after some looking things up i now got to this:

running wireshark with 'capture packets in promiscuous mode' enabled, and dhcp works ... running wireshark without (or not running wireshark at all) -> dhcp does not work...

so far... but i do not know, how to use this knowledge to get this to work without the wireshark-trick...
at least it seems to be something like the wlan-device does not listen to dhcp-acknoledge-packets (or the more general group of not-addressed-to-me-via-ip-packets) unless wireshark forces it to... but i don't think, this should be the default behaviour...
and i also do not know, if i could have something misconfigured that strange, that it only affects this chip with this kernel version...

MoonSwan · 2012-06-23 17:31:03

Does running

rfkill --list or rfkill -l

show that one of your wlan0's ports closed by hard or soft block? If they do you can just tell rfkill to unblock them. Running

rfkill --help

will show you how to do that. I know I've had that happen in the past and the first time it did I spent an hour trying to debug the damned thing! But back a few years ago I had no idea what rfkill did either.

I found that using the current kernel can be problematic with Atheros USB devices (well, mine at least, as I too use ath9k but a different driver [9170Carl I think]). When I figured out that the LTS kernel will usually work fine with it when the main kernel will not I decided to use just the LTS kernel. I've not had issues since then with my USB NIC. Try that perhaps.

Someone posted a while ago that he got his USB NIC to work by adding in to rc.local a line underneath his wireless driver's instructions a simple "dhcp" instruction. You may need to search for that because I'm not too clear about what he did, sorry.

Found it! https://bbs.archlinux.org/viewtopic.php?id=143774

Last edited by MoonSwan (2012-06-23 17:36:31)

stevepa · 2012-06-24 02:21:26

An interesting discovery I made is that my Atheros card works perfectly in a just installed system, but is problematic in a upgraded system.

HTH
Steve.

tequa · 2012-06-24 11:46:36

Hello,

i tried the rfkill, but it seems there is nothing blocked:

> rfkill list
0: phy0: Wireless LAN
	Soft blocked: no
	Hard blocked: no

... and i read a bit further about this wireshark trick... and now it seems to me, that it has got nothing to do with the IP-Broadcast, but with the MAC-Broadcast (or however it is called) ... because the Adaptor seems to ignore broadcastet packets (DHCP-Ack and ARP-requests), which is a problem too, as my pc is no longer reachable for others in the same network, because the adaptor ignores the ARP-requests, too...

and just because i recently updated: it still does not work with kernel 3.4.4 ...

but thank you so far (i did not know about rfkill up to now)

tequa · 2012-06-24 12:07:29

Hey, i at least found a workaround so far... as this 'promiscuous mode' seems to solve the problem temporarily, i have to set this manually before connecting:

so here the last line of my netcfg-profile for this wlan:

PRE_UP="ifconfig wlan0 promisc"

But i am still convinced, that this should not be necessary and has to be some kind of bug...

trogdor · 2012-06-26 12:42:54

Thanks for the tip tequa been trying to find a way to fix this for days.

MoonSwan · 2012-06-26 18:59:56

My only other suggestion is to try using the LTS kernel. I use LTS because my wireless does not break too darn often with it. With the main kernel I've experienced more breakage than I care to admit. My USB nic is also an Atheros (9170Carl) to be precise. Its a DLink DWA160A2 [the A2 is Firmware v. A2]. The FW: A2 is important because the original nic [FW v A1] used a flaky chipset. The A2 uses an Atheros chip that has worked pretty flawlessly for a year now. I have other USB nics laying about that a friend gave me and the only other one I've used that is very stable is the RALink series which use chips that use the RT2x00 drivers.

zigiless · 2012-07-11 16:07:54

Anyone find a permanent solution yet?

Gusar · 2012-07-11 16:12:27

https://bbs.archlinux.org/viewtopic.php … 0#p1121640

Arch Linux

#1 2012-06-23 10:09:42

DHCP does not work anymore with kernel 3.4.2+ for ath9k-WLAN-USB

#2 2012-06-23 11:17:36

Re: DHCP does not work anymore with kernel 3.4.2+ for ath9k-WLAN-USB

#3 2012-06-23 17:31:03

Re: DHCP does not work anymore with kernel 3.4.2+ for ath9k-WLAN-USB

#4 2012-06-24 02:21:26

Re: DHCP does not work anymore with kernel 3.4.2+ for ath9k-WLAN-USB

#5 2012-06-24 11:46:36

Re: DHCP does not work anymore with kernel 3.4.2+ for ath9k-WLAN-USB

#6 2012-06-24 12:07:29

Re: DHCP does not work anymore with kernel 3.4.2+ for ath9k-WLAN-USB

#7 2012-06-26 12:42:54

Re: DHCP does not work anymore with kernel 3.4.2+ for ath9k-WLAN-USB

#8 2012-06-26 18:59:56

Re: DHCP does not work anymore with kernel 3.4.2+ for ath9k-WLAN-USB

#9 2012-07-11 16:07:54

Re: DHCP does not work anymore with kernel 3.4.2+ for ath9k-WLAN-USB

#10 2012-07-11 16:12:27

Re: DHCP does not work anymore with kernel 3.4.2+ for ath9k-WLAN-USB

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