Re: Wireless IBSS on Linux-2.6.34 broken by commit 3bbb9ec946428b96657126768f65487a48dd090c

From: Jeff Chua
Date: Sun May 23 2010 - 09:19:25 EST

> On Sun, 2010-05-23 at 05:58 +0100, Jeff Chua wrote:
> Wireless IBSS on Linux-2.6.34 is broken. Reverting commit
> 3bbb9ec946428b96657126768f65487a48dd090c makes it work again. This was
> tested by bisecting the kernel.

On Sun, May 23, 2010 at 2:21 PM, Arjan van de Ven <arjan@xxxxxxxxxxxxxxx> wrote:
> can you get us whole dmesg of two cases?
> (just to know if there's something in surrounding messages of interest)

On Sun, May 23, 2010 at 5:49 PM, Johannes Berg <johannes.berg@xxxxxxxxx> wrote:
> This is odd -- as Arjan said more logging would be good, if you can
> enable mac80211 IBSS debug (though in one case we had recently that
> _fixed_ the issue unfortunately) -- it's under the mac80211 debug menu
> Kconfig.
> FWIW, I don't know about anything in mac80211 that would be timer
> sensitive?

Arjan, Johannes,

Here's the dmesg I see. The only difference between the non-working
and working ones are the last 4 lines below with the bad commit
reverted. With the non-working one, I don't see the last 4 lines no
matter how long I waited.
And I'm guessing it's something to do with mod_timer() that modified
the timer's timeout. mod_timer() is used by by both iwlwifi amd
mac80211. I'll get the full mac80211 debug soon.

2010-05-22T11:42:55.129641+08:00 boston kernel: cfg80211: Calling CRDA
to update world regulatory domain
2010-05-22T11:42:55.162713+08:00 boston kernel: iwlagn: Intel(R)
Wireless WiFi Link AGN driver for Linux, in-tree:
2010-05-22T11:42:55.162782+08:00 boston kernel: iwlagn: Copyright(c)
2003-2010 Intel Corporation
2010-05-22T11:42:55.162785+08:00 boston kernel: iwlagn 0000:02:00.0:
PCI INT A -> GSI 16 (level, low) -> IRQ 16
2010-05-22T11:42:55.162788+08:00 boston kernel: iwlagn 0000:02:00.0:
setting latency timer to 64
2010-05-22T11:42:55.162814+08:00 boston kernel: iwlagn 0000:02:00.0:
Detected Intel Wireless WiFi Link 6000 Series 2x2 AGN REV=0x74
2010-05-22T11:42:55.182139+08:00 boston kernel: iwlagn 0000:02:00.0:
Tunable channels: 13 802.11bg, 24 802.11a channels
2010-05-22T11:42:55.182164+08:00 boston kernel: iwlagn 0000:02:00.0:
irq 44 for MSI/MSI-X
2010-05-22T11:42:55.182169+08:00 boston kernel: iwlagn 0000:02:00.0:
firmware: requesting iwlwifi-6000-4.ucode
2010-05-22T11:42:55.198654+08:00 boston kernel: iwlagn 0000:02:00.0:
loaded firmware version
2010-05-22T11:42:55.201637+08:00 boston kernel: phy0: Selected rate
control algorithm 'iwl-agn-rs'
2010-05-22T11:42:57.538644+08:00 boston kernel: wlan0: Trigger new
scan to find an IBSS to join

(*** These shows up for the working kernel with bad commit removed ***)
2010-05-22T11:43:04.797649+08:00 boston kernel: wlan0: Trigger new
scan to find an IBSS to join
2010-05-22T11:43:08.149646+08:00 boston kernel: wlan0: Creating new
IBSS network, BSSID 46:9a:67:c7:5d:30
2010-05-22T11:43:08.207216+08:00 boston kernel: iwlagn 0000:02:00.0:
Unable to find TIM Element in beacon
2010-05-22T11:43:08.207232+08:00 boston kernel: iwlagn 0000:02:00.0:
Unable to find TIM Element in beacon

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at