Re: [cfg80211 / iwlwifi] setting wireless regulatory domain doesn't work.

From: Sander Eikelenboom
Date: Wed Dec 11 2013 - 10:17:22 EST

Since i haven't got a response to this yet and after having the troubled machine back:
The problem is still present in linux 3.13-rc3

The problem seems to be in this piece of code:

root@creabox:/usr/src/linux-tip# git blame -L 1567,1601 net/wireless/reg.c
fe33eb39 (Luis R. Rodriguez 2009-02-21 00:04:30 -0500 1567)
b2e253cf (Luis R. Rodriguez 2010-11-17 21:46:09 -0800 1568) /*
b2e253cf (Luis R. Rodriguez 2010-11-17 21:46:09 -0800 1569) * Processes regulatory hints, this is all the NL80211_REGDOM_SET_BY_*
b2e253cf (Luis R. Rodriguez 2010-11-17 21:46:09 -0800 1570) * Regulatory hints come on a first come first serve basis and we
b2e253cf (Luis R. Rodriguez 2010-11-17 21:46:09 -0800 1571) * must process each one atomically.
b2e253cf (Luis R. Rodriguez 2010-11-17 21:46:09 -0800 1572) */
fe33eb39 (Luis R. Rodriguez 2009-02-21 00:04:30 -0500 1573) static void reg_process_pending_hints(void)
b0e2880b (Luis R. Rodriguez 2010-11-17 21:46:08 -0800 1574) {
c492db37 (Johannes Berg 2012-12-06 16:29:25 +0100 1575) struct regulatory_request *reg_request, *lr;
fe33eb39 (Luis R. Rodriguez 2009-02-21 00:04:30 -0500 1576)
c492db37 (Johannes Berg 2012-12-06 16:29:25 +0100 1577) lr = get_last_request();
b0e2880b (Luis R. Rodriguez 2010-11-17 21:46:08 -0800 1578)
b2e253cf (Luis R. Rodriguez 2010-11-17 21:46:09 -0800 1579) /* When last_request->processed becomes true this will be rescheduled */
c492db37 (Johannes Berg 2012-12-06 16:29:25 +0100 1580) if (lr && !lr->processed) {
1a919318 (Johannes Berg 2012-12-03 17:21:11 +0100 1581) REG_DBG_PRINT("Pending regulatory request, waiting for it to be processed...\n");
5fe231e8 (Johannes Berg 2013-05-08 21:45:15 +0200 1582) return;

If i "comment out" the return above, setting the regulatory domain with "iw reg set XX" does work.

b2e253cf (Luis R. Rodriguez 2010-11-17 21:46:09 -0800 1583) }
b2e253cf (Luis R. Rodriguez 2010-11-17 21:46:09 -0800 1584)
fe33eb39 (Luis R. Rodriguez 2009-02-21 00:04:30 -0500 1585) spin_lock(&reg_requests_lock);
fe33eb39 (Luis R. Rodriguez 2009-02-21 00:04:30 -0500 1586)
b2e253cf (Luis R. Rodriguez 2010-11-17 21:46:09 -0800 1587) if (list_empty(&reg_requests_list)) {
d951c1dd (Luis R. Rodriguez 2009-02-21 00:24:15 -0500 1588) spin_unlock(&reg_requests_lock);
5fe231e8 (Johannes Berg 2013-05-08 21:45:15 +0200 1589) return;
fe33eb39 (Luis R. Rodriguez 2009-02-21 00:04:30 -0500 1590) }
b2e253cf (Luis R. Rodriguez 2010-11-17 21:46:09 -0800 1591)
b2e253cf (Luis R. Rodriguez 2010-11-17 21:46:09 -0800 1592) reg_request = list_first_entry(&reg_requests_list,
b2e253cf (Luis R. Rodriguez 2010-11-17 21:46:09 -0800 1593) struct regulatory_request,
b2e253cf (Luis R. Rodriguez 2010-11-17 21:46:09 -0800 1594) list);
b2e253cf (Luis R. Rodriguez 2010-11-17 21:46:09 -0800 1595) list_del_init(&reg_request->list);
b2e253cf (Luis R. Rodriguez 2010-11-17 21:46:09 -0800 1596)
fe33eb39 (Luis R. Rodriguez 2009-02-21 00:04:30 -0500 1597) spin_unlock(&reg_requests_lock);
b0e2880b (Luis R. Rodriguez 2010-11-17 21:46:08 -0800 1598)
8848bef0 (Luis R. Rodriguez 2011-12-20 12:23:36 -0800 1599) reg_process_hint(reg_request, reg_request->initiator);
fe33eb39 (Luis R. Rodriguez 2009-02-21 00:04:30 -0500 1600) }
fe33eb39 (Luis R. Rodriguez 2009-02-21 00:04:30 -0500 1601)

--
Sander


Wednesday, October 23, 2013, 2:28:49 PM, you wrote:

> Ping ?

> Friday, October 18, 2013, 7:43:49 PM, you wrote:

>> Hi,

>> I'm trying to change the regulatory domain for my wireless adapter:
>> Intel Corporation Centrino Advanced-N 6235

>> But it fails to change from "world" to anything else (say "US")

>> I enabled debug options used iwlwifi.debug=0x00043FFF for boot and added some printk's which i think should be triggered .. but they are not.
>> It seems in function "reg_process_pending_hints" the processing is deferred,
>> but from the code i don't see how it would ever be triggered to complete ?

>> Hope some can give some hints to what could be going on ...

>> Attached:
>> - full syslog from boot till "iw set reg US", which is done at "Oct 18 21:26:09"
>> - patch.diff with the added debug printk's against 3.12-rc5 (it also contains the patch that was needed to suppress another warning in the iwlwifi driver.

>> --
>> Sander

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