From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from s3.sipsolutions.net ([5.9.151.49]:52932 "EHLO sipsolutions.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965842AbcKXPMV (ORCPT ); Thu, 24 Nov 2016 10:12:21 -0500 Message-ID: <1480000334.4388.2.camel@sipsolutions.net> (sfid-20161124_161237_579769_23AE43E1) Subject: Re: many "changed bandwidth, new config is" messages in the log From: Johannes Berg To: Michal Hocko Cc: LKML , linux-wireless Date: Thu, 24 Nov 2016 16:12:14 +0100 In-Reply-To: <20161124150723.GA4776@dhcp22.suse.cz> References: <20161124150723.GA4776@dhcp22.suse.cz> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Sender: linux-wireless-owner@vger.kernel.org List-ID: On Thu, 2016-11-24 at 15:07 +0000, Michal Hocko wrote: > I have only now managed to move to 4.9-rc5 (from 4.8) and started > seeing quite a lot of following messages > " > [  346.612211] wlan0: AP c0:4a:00:f1:48:f2 changed bandwidth, new > config is 2472 MHz, width 1 (2472/0 MHz) > [  352.655929] wlan0: AP c0:4a:00:f1:48:f2 changed bandwidth, new > config is 2472 MHz, width 2 (2462/0 MHz) > " I don't think these messages are new in any way. checking ... nope, it's been around that way since 3.9 :-) > It always seems to be changing width from 1 -> 2 and back Makes sense, that's 20 MHz <-> 40 MHz. Did you buy a new device that says it's 40 MHz incompatible or something? Or perhaps one of your neighbors did ... Or something is causing interference that makes the AP switch around. > $ dmesg | grep "changed bandwidth" | wc -l > 42 > in 13 minutes of uptime. I have noticed this came in via 30eb1dc2c430 > ("mac80211: properly track HT/VHT operation changes"). Right, but that went into 3.9 :-) > Is this something to be worried about? Not at all. I suppose we could make this a debug message though, it's not super useful when it happens OK (sometimes it causes disconnections when we can't support the new mode, which is more relevant). johannes