Re: [gentoo-user] Unable to set wireless regulatory domain

[John Nielsen <lists@jnielsen.net>]

On May 6, 2011, at 4:14 PM, Mick wrote:

> On Friday 06 May 2011 18:04:31 John Nielsen wrote:
>> Doesn't look like this went through the first time; re-sending without
>> attachment.
>> 
>> On May 5, 2011, at 6:52 PM, Paul Hartman wrote:
>>> On Thu, May 5, 2011 at 12:40 PM, John Nielsen <lists@jnielsen.net> wrote:
>>>> I am trying to set up a 5GHz wireless access point on an Alix 3d2 board
>>>> with an AR9220 (ath9k "Merlin") PCI card. I have done so successfully
>>>> using Fedora 14 on identical hardware but I would greatly prefer to use
>>>> Gentoo so I can use a more recent kernel and customize things
>>>> appropriately for the platform.
>>> 
>>> It seems like everything is pretty much the same, other than the
>>> kernel (and presumably the ath9k driver). But I would look at the udev
>>> rules for CRDA to be sure they match and are being applied the same on
>>> both systems. You shouldn't ever need to "iw reg set" on a system with
>>> CRDA, it should do it for you. So I wonder if you're setting it, and
>>> then CRDA is immediately setting it back to 00...
>> 
>> The udev rule for CRDA is the same on both systems, and matches what is
>> shown on http://wireless.kernel.org/en/developers/Regulatory/CRDA. The
>> Fedora box also has a magic rule to call /sbin/setregdomain when an 80211
>> interface is added, which is a shell script that infers the regdomain from
>> the currently set timezone. The punch line of the script is simply a call
>> to "iw reg set $COUNTRY"
>> 
>> However, I'm not sure crda is being called appropriately on the Gentoo box. 
> On the Fedora machine I see this in dmesg:
>>>> [   17.248674] cfg80211: Calling CRDA for country: US
>>>> [   18.848206] cfg80211: Regulatory domain changed to country: US
>> 
>> and I don't ever see anything similar on the Gentoo machine, even when
>> running "iw reg set" by hand. Further, I don't see anything in the output
>> of "udevadm monitor --environment kernel".
>> 
>> I just dropped the kernel from the Fedora machine on to the Gentoo box and
>> (somewhat surprisingly) it works just fine. The reg domain gets set no
>> problem, hostapd starts, life is good--except that now I feel like I've
>> sinned against nature and I'd like to get my own, smaller kernel back.
>> 
>> While it's possible the new kernel version is broken I rather suspect that
>> I have configured it badly. I set out to configure a minimal kernel with
>> just the features and drivers I want on this hardware and no need for
>> modules or an initramfs. Does cfg80211 need to be a module to work
>> properly? I wouldn't think so.
>> 
>> I'll do some more experimenting but in the mean time here's my kernel
>> config in case anyone has ideas on what could be wrong. Thanks!
>> 
>> Config file here: http://pastebin.com/S68ye6Pz
> 
> I suggest that you run a diff --suppress-common-lines -y between the Fedora 
> and your own kernel to find out what's different between the two as far as 
> your driver is concerned.

The outright diff was far too verbose to be useful, but looking at "lsmod" output when running the Fedora kernel was instructive. I recognized everything as being in by Gentoo kernel except for "rfkill", which was listed as a dependency of cfg80211. Long story short, I got it working like I want by:

1) Including RFKILL in my kernel config and
2) Building cfg80211, mac80211, rfkill, and all parts of the ath9k driver as modules

Just adding RFKILL to a static (module-less) kernel didn't fix it, and just building cfg80211 and friends as modules without RFKILL also didn't fix it; I had to do both.

Thanks all for your responses so far. I'll be happy to ditch Fedora. :)

For future reference, does anyone know why either of the above would be required? If I see the same behavior in the latest git kernel should I file a bug? If so, where (since I doubt this is a Gentoo issue)?

JN