Return-path: Received: from mail-io0-f182.google.com ([209.85.223.182]:36535 "EHLO mail-io0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752673AbbI3RCy (ORCPT ); Wed, 30 Sep 2015 13:02:54 -0400 MIME-Version: 1.0 Date: Wed, 30 Sep 2015 13:02:53 -0400 Message-ID: (sfid-20150930_190316_251750_D94A662B) Subject: Rate limiting AP bandwidth change messages in ieee80211_config_bw? From: Josh Boyer To: Johannes Berg Cc: drago01 , "linux-wireless@vger.kernel.org" , netdev , "Linux-Kernel@Vger. Kernel. Org" Content-Type: text/plain; charset=UTF-8 Sender: linux-wireless-owner@vger.kernel.org List-ID: Hi Johannes, We've seen a handful of reports that seem to have verbose output from the ieee80211_config_bw function in net/mac80211/mlme.c. It looks similar to this: [ 66.578652] wlp3s0: AP xx:xx:xx:xx:xx changed bandwidth, new config is 2437 MHz, width 2 (2447/0 MHz) [ 68.522437] wlp3s0: AP xx:xx:xx:xx:xx changed bandwidth, new config is 2437 MHz, width 1 (2437/0 MHz) [ 69.548353] wlp3s0: AP xx:xx:xx:xx:xx changed bandwidth, new config is 2437 MHz, width 2 (2447/0 MHz) [ 70.568677] wlp3s0: AP xx:xx:xx:xx:xx changed bandwidth, new config is 2437 MHz, width 1 (2437/0 MHz) [ 71.489416] wlp3s0: AP xx:xx:xx:xx:xx changed bandwidth, new config is 2437 MHz, width 2 (2447/0 MHz) [ 72.512917] wlp3s0: AP xx:xx:xx:xx:xx changed bandwidth, new config is 2437 MHz, width 1 (2437/0 MHz) [ 73.535866] wlp3s0: AP xx:xx:xx:xx:xx changed bandwidth, new config is 2437 MHz, width 2 (2447/0 MHz) [ 81.777530] wlp3s0: AP xx:xx:xx:xx:xx changed bandwidth, new config is 2437 MHz, width 1 (2437/0 MHz) [ 82.540576] wlp3s0: AP xx:xx:xx:xx:xx changed bandwidth, new config is 2437 MHz, width 2 (2447/0 MHz) [ 94.513467] wlp3s0: AP xx:xx:xx:xx:xx changed bandwidth, new config is 2437 MHz, width 1 (2437/0 MHz) [ 95.634855] wlp3s0: AP xx:xx:xx:xx:xx changed bandwidth, new config is 2437 MHz, width 2 (2447/0 MHz) [ 97.474767] wlp3s0: AP xx:xx:xx:xx:xx changed bandwidth, new config is 2437 MHz, width 1 (2437/0 MHz) [ 98.498036] wlp3s0: AP xx:xx:xx:xx:xx changed bandwidth, new config is 2437 MHz, width 2 (2447/0 MHz) [ 99.520472] wlp3s0: AP xx:xx:xx:xx:xx changed bandwidth, new config is 2437 MHz, width 1 (2437/0 MHz) [ 100.551344] wlp3s0: AP xx:xx:xx:xx:xx changed bandwidth, new config is 2437 MHz, width 2 (2447/0 MHz) [ 101.571100] wlp3s0: AP xx:xx:xx:xx:xx changed bandwidth, new config is 2437 MHz, width 1 (2437/0 MHz) [ 102.490708] wlp3s0: AP xx:xx:xx:xx:xx changed bandwidth, new config is 2437 MHz, width 2 (2447/0 MHz) Essentially, this looks like the AP is changing the bandwidth (and only the width) every second or so. Why it is doing this, I'm not sure. However, this doesn't seem to actually be an error case yet the kernel logs are getting spammed with this message. I'm wondering if we could either change this message to use sdata_dbg instead of sdata_info, or if we could possibly ratelimit it somehow. I'd be happy to come up with a patch for either, but I wanted to get your feedback on it before I started. Do you have any objections or preference? josh