Return-path: Received: from mail-fx0-f46.google.com ([209.85.161.46]:62979 "EHLO mail-fx0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753795Ab0LFRmS (ORCPT ); Mon, 6 Dec 2010 12:42:18 -0500 Received: by fxm20 with SMTP id 20so4419240fxm.19 for ; Mon, 06 Dec 2010 09:42:17 -0800 (PST) From: Christian Lamparter To: Wade Fitzpatrick Subject: Re: ar9170usb slow / poor performance (SOLVED) Date: Mon, 6 Dec 2010 18:41:57 +0100 Cc: linux-wireless@vger.kernel.org References: In-Reply-To: MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Message-Id: <201012061841.58047.chunkeey@googlemail.com> Sender: linux-wireless-owner@vger.kernel.org List-ID: On Monday 06 December 2010 17:34:15 Wade Fitzpatrick wrote: > I could not get anything sensible from carl9170. I will keep trying though. hmm, hard to say what it is? I bet it could be conflicting stack/driver modules. (i.e.: the driver is from compact-wireless, whereas the mac80211, or cfg80211 is the original module from 2.6.36) > The Otus message comes from arusb_lnx which was loaded automatically > after ar9170usb. Should I remove the arusb_lnx.ko file? either that, or add it to the module blacklist (also in /etc/modprobe.d) > I did not patch the driver as I am not clear what MCS and minstrel_ht are. #Data Rates "Data rates up to 600 Mbit/s are achieved only with the maximum of four spatial streams using a 40 MHz-wide channel. Various modulation schemes and coding rates are defined by the standard and are represented by a Modulation and Coding Scheme (MCS) index value." minstrel* is mac80211's default rate control algorithm. The original minstrel only supports legacy (802.11a/b/g) data rates and minstrel_ht only selects 802.11n MCS (index). > Simply unloading the modules and modprobing them again does not work > reliably. I think it must be due to not reloading the firmware > properly. The ar9170usb, otus and all windows-driver firmware will only be uploaded once (on the first time a driver is loaded). All later upload attempts are ignored. The problem here is that the firmware program can't be easily replaced "in-place" without breaking compatibility or functionality. > I added the mac80211 options to modprobe.conf and after rebooting, > both wireless dongles are stable and ping times are back to normal for > the ar9170usb driver. no need to reboot, you can unload modules with modprobe -r / rmmod [as long as the modules are not in use, or an other loaded module depends on it]. > # > # /etc/modprobe.d/modprobe.conf (for v2.6 kernels) > # > options mac80211 ieee80211_default_rc_algo=minstrel the problem with this is that carl9170 (or any other driver that relies on minstrel_ht to supply 802.11n MCS rates) are limited to the legacy rates (and physpeeds of 54Mbit) > BTW - my AP is a Netgear WNR2000v2 > I can do further testing if you would like me to. Well, we had a funny incidents with WNDR3700. after some initial problems with WMM, he got it sort-of-working. This "sort-of" should be fixed now: Best regards, Christian