Ubuntu

bcmwl/brcm80211 can't see wifi channels >11 (2.462GHz)

Reported by Daniel van Vugt on 2011-02-05
38
This bug affects 8 people
Affects Status Importance Assigned to Milestone
Mactel Support
Undecided
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bcmwl (Ubuntu)
Undecided
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Bug Description

Can't see channels >11 (2.462GHz) any more. Channels 1-11 still work, but 12 and 13 are invisible to both "iwlist scan" and network manager now.

The problem seems to be new in natty (alpha 2) with bcmwl-kernel-source 5.100.82.38+bdcom-0ubuntu2. However maverick with 5.60.48.36+bdcom-0ubuntu5 can see the access point on any channel no problem.

System is a Macbook Air 3,1 with PCI device:
01:00.0 Network controller: Broadcom Corporation BCM43224 802.11a/b/g/n (rev 01)
[01:00.0 0280: 14e4:4353 (rev 01)]

ProblemType: Bug
DistroRelease: Ubuntu 11.04
Package: bcmwl-kernel-source 5.100.82.38+bdcom-0ubuntu2
ProcVersionSignature: Ubuntu 2.6.38-1.28-generic 2.6.38-rc2
Uname: Linux 2.6.38-1-generic x86_64
NonfreeKernelModules: nvidia wl
Architecture: amd64
Date: Sat Feb 5 16:12:41 2011
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Alpha amd64 (20110202)
ProcEnviron:
 LANGUAGE=en_AU:en
 PATH=(custom, no user)
 LANG=en_AU.UTF-8
 LC_MESSAGES=en_AU.utf8
 SHELL=/bin/bash
SourcePackage: bcmwl

Daniel van Vugt (vanvugt) wrote :
Daniel van Vugt (vanvugt) wrote :

Seemingly confirmed by Broadcom themselves...

The new driver "brcm80211" which first appeared in kernel 2.6.38, and apparently first enabled in natty-beta-1 suffers from this same issue.

This led me to comments from Broadcom developers explaining why channels >11 are disabled by default:
"Regulatory Implementation
This generation of chips contain additional regulatory support independent of the driver. The devices use a single worldwide regulatory domain, with channels 12-14 (2.4 GHz band) and channels 52-64 and 100-140 (5 GHz band) restricted to passive operation. Transmission on those channels is suppressed until appropriate other traffic is observed on those channels."
[http://linuxwireless.org/en/users/Drivers/brcm80211]

I think it is safe to assume that Broadcom disabled channels >11 in (bcm)wl also, for the same reason. So the bug is confirmed and intentional, for radio regulatory compliance :(

summary: - bcmwl can't see channels > 11 (2.462GHz) any more
+ bcmwl/brcm80211 can't see wifi channels >11 (2.462GHz)
Changed in bcmwl (Ubuntu):
status: New → Confirmed
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