FS#14013 - cannot enter Ad-Hoc mode on intel 4965

Attached to Project: Arch Linux
Opened by Ayla Ounce (reacocard) - Sunday, 29 March 2009, 19:57 GMT
Last edited by Tobias Powalowski (tpowa) - Friday, 10 April 2009, 16:59 GMT
Task Type Bug Report
Category Packages: Testing
Status Closed
Assigned To Tobias Powalowski (tpowa)
Thomas Bächler (brain0)
Architecture All
Severity Medium
Priority Normal
Reported Version
Due in Version Undecided
Due Date Undecided
Percent Complete 100%
Votes 0
Private No

Details

On the 2.6.29-3 kernel from testing, I can no longer put my intel 4965agn wifi card into Ad-Hoc mode. It fails with the following message:

reacocard@cogito:~$ sudo iwconfig wlan0 mode Ad-Hoc
Error for wireless request "Set Mode" (8B06) :
SET failed on device wlan0 ; Operation not supported

I did not experience this issue in 2.6.28 or in my custom built 2.6.29-rc7 and -rc8 kernels.
This task depends upon

Closed by  Tobias Powalowski (tpowa)
Friday, 10 April 2009, 16:59 GMT
Reason for closing:  Not a bug
Comment by Tobias Powalowski (tpowa) - Monday, 06 April 2009, 13:19 GMT
Are you already using crda for wireless configuration?
Comment by Thomas Bächler (brain0) - Monday, 06 April 2009, 15:42 GMT
Tobias, crda is only for regulation, it is unrelated to IBSS mode (except that it allows and disallows certain channels).
Comment by Ayla Ounce (reacocard) - Monday, 06 April 2009, 16:00 GMT
no I am not using crda.
Comment by Thomas Bächler (brain0) - Friday, 10 April 2009, 09:58 GMT
Okay, I understand the issue now: The default "World" regulation built into the kernel does not allow active scanning or IBSS on any channel and thus disables IBSS mode altogether. If you enter "iw list", you will see something like this:

Wiphy phy0
Band 1:
Frequencies:
* 2412 MHz [1] (20.0 dBm) (passive scanning, no IBSS)
* 2417 MHz [2] (20.0 dBm) (passive scanning, no IBSS)
* 2422 MHz [3] (20.0 dBm) (passive scanning, no IBSS)
* 2427 MHz [4] (20.0 dBm) (passive scanning, no IBSS)
* 2432 MHz [5] (20.0 dBm) (passive scanning, no IBSS)
* 2437 MHz [6] (20.0 dBm) (passive scanning, no IBSS)
* 2442 MHz [7] (20.0 dBm) (passive scanning, no IBSS)
* 2447 MHz [8] (20.0 dBm) (passive scanning, no IBSS)
* 2452 MHz [9] (20.0 dBm) (passive scanning, no IBSS)
* 2457 MHz [10] (20.0 dBm) (passive scanning, no IBSS)
* 2462 MHz [11] (20.0 dBm) (passive scanning, no IBSS)
* 2467 MHz [12] (disabled)
* 2472 MHz [13] (disabled)
* 2484 MHz [14] (disabled)
Bitrates:
* 1.0 Mbps
* 2.0 Mbps
* 5.5 Mbps
* 11.0 Mbps
* 6.0 Mbps
* 9.0 Mbps
* 12.0 Mbps
* 18.0 Mbps
* 24.0 Mbps
* 36.0 Mbps
* 48.0 Mbps
* 54.0 Mbps
Supported interface modes:
* Station
* Monitor

Solution: Install the crda package, edit /etc/conf.d/wireless-regdom, uncomment your country there and run /etc/rc.d/wireless-regdom start once (a reboot will also work). Then run "iw list" again and see that you are now allowed to use IBSS again. With the current regdom updates from crda, you are even allowed to use IBSS in the "World" regulatory domain, but the static one built into the kernel is older or more restrictive than that.
Comment by Ayla Ounce (reacocard) - Friday, 10 April 2009, 14:50 GMT
I can confirm that installing crda and setting a regdom does indeed resolve the issue. Thanks!

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