[ath9k-devel] AR9380 + hostapd + HT over 802.11a

[Mihai Moldovan <ionic@ionic.de>]

Ok, some more information.

Kernel: 2.6.38.6

I first thought of a race condition, as the cfg80211 subsystem tries to 
get an updated world entry of the regdb pretty early. However, at that 
time udev was already started:

[   14.319904] udev: starting version 151
[   14.319960] udevd (2041): /proc/2041/oom_adj is deprecated, please 
use /proc/2041/oom_score_adj instead.
[   14.613461]  md2: unknown partition table
[   14.617229] cfg80211: Calling CRDA to update world regulatory domain
[   14.645768] e1000e: Intel(R) PRO/1000 Network Driver - 1.2.20-k2
[   14.645771] e1000e: Copyright(c) 1999 - 2011 Intel Corporation.
...

Interestingly, cfg80211 wants to update the world regdom right before 
loading another network interface module (e1000e), which is a wired 
interface. Could this cause problems?


This call obviously never returns, as regdomain changes afterwards are 
all queued but will never be acted upon:

[   18.262657] cfg80211: Pending regulatory request, waiting for it to 
be processed...
(and several other of those messages)

In order to see whether udev gets a regulatory change event, I enabled 
udevadm monitoring and came to this conclusion:

KERNEL[1306936946.968633] add      /module/cfg80211 (module)
UDEV_LOG=3
ACTION=add
DEVPATH=/module/cfg80211
SUBSYSTEM=module
SEQNUM=2849

KERNEL[1306936946.968645] add      /class/ieee80211 (class)
UDEV_LOG=3
ACTION=add
DEVPATH=/class/ieee80211
SUBSYSTEM=class
SEQNUM=2850

KERNEL[1306936946.968711] add      /devices/platform/regulatory.0 (platform)
UDEV_LOG=3
ACTION=add
DEVPATH=/devices/platform/regulatory.0
SUBSYSTEM=platform
MODALIAS=platform:regulatory
SEQNUM=2851

KERNEL[1306936946.968750] change   /devices/platform/regulatory.0 (platform)
UDEV_LOG=3
ACTION=change
DEVPATH=/devices/platform/regulatory.0
SUBSYSTEM=platform
COUNTRY=00
MODALIAS=platform:regulatory
SEQNUM=2852

UDEV  [1306936946.968830] add      /module/cfg80211 (module)
UDEV_LOG=3
STARTUP=1
ACTION=add
DEVPATH=/module/cfg80211
SUBSYSTEM=module
SEQNUM=2849

UDEV  [1306936946.968902] add      /class/ieee80211 (class)
UDEV_LOG=3
STARTUP=1
ACTION=add
DEVPATH=/class/ieee80211
SUBSYSTEM=class
SEQNUM=2850

UDEV  [1306936946.969934] add      /devices/platform/regulatory.0 (platform)
UDEV_LOG=3
STARTUP=1
ACTION=add
DEVPATH=/devices/platform/regulatory.0
SUBSYSTEM=platform
MODALIAS=platform:regulatory
SEQNUM=2851

So, yep, udev is getting the change requests (two actually, as both 
ath9k cards are added to the system.)

The rule should work fine too:

KERNEL=="regulatory*", ACTION=="change", SUBSYSTEM=="platform", 
RUN+="/sbin/crda"

Nothing broken here.

One last thing I'll try is removing one ath9k card to see whether it 
works with one card only. Maybe ath9k or cfg80211 is broken here when 
using multiple cards at the same time.

Other than that, I'm out of ideas.

As far as I know, Luis is good with this CRDA stuff, so I'll CC him, 
just to make sure I'm not missing anything.

I tried crda versions 1.0.1, 1.1.1 and git, though the behavior was the 
same throughout all versions.

Posting results with one card only soon.

Best regards and thanks,


Mihai

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