Return-path: Received: from mail-fx0-f217.google.com ([209.85.220.217]:41712 "EHLO mail-fx0-f217.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751004AbZHaRzz (ORCPT ); Mon, 31 Aug 2009 13:55:55 -0400 Received: by fxm17 with SMTP id 17so2920972fxm.37 for ; Mon, 31 Aug 2009 10:55:56 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: References: Date: Mon, 31 Aug 2009 18:55:56 +0100 Message-ID: <3ace41890908311055s5c49a25fjf69ca48024579d44@mail.gmail.com> Subject: Re: rtl8187b Problem with tx level From: Hin-Tak Leung To: Tobias Schlemmer Cc: linux-wireless@vger.kernel.org Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-wireless-owner@vger.kernel.org List-ID: On Sun, Aug 30, 2009 at 9:44 PM, Tobias Schlemmer wrote: > Hi, > > I have some problem with my rtl8187b device. It is included in my laptop > running Ubuntu linux 2.6.28. I've tested several compat-wireless releases > including 2.6.30 and 2.6.31-rc7. Hmm, are compat-wireless versioned against kernels? I thought they just have dates and git describe tags. Could you try the latest-and-greatest? (the latest and greatest is ahead of 2.6.31-rc7 by a few months) http://linuxwireless.org/en/users/Download > The problem is that the network adapter looses the connection to the access > point at very low distances. It seems to be as if the driver is too > optimistic about tx power. I monitored the singnal strength on the access > point (Buffalo running DD-WRT). When I associate the laptop with it the > recieved signal strength starts full and drops rapidly in the first seconds. > At the end it is about 0 at a distance of 4m. At this moment no ping will > arrive the destination. Tests with other access points show similar results. > > After several attempts to get different drivers working I used an Ubuntu > 8.04 boot CD this morning which seems to work out of the box. It has kernel > 2.6.24 using a module called r8187. I compared these two drivers and got > much better signal strengths, at least more stable connections. Maybe it's > interesting that the two drivers report different signal strength > (compat-wireless reports about 10dBm higher values than the old driver) also > in signal quality the compat wireless driver seems to be more optimistic. We are familiar with the r8187 module - what version did Ubuntu ship? (the module headers are not updated so modinfo is useless). I see you have the mesh code so that's quite recent. I have compat-wireless from a few days ago, and iwconfig says - Bit Rate=11 Mb/s Tx-Power=20 dBm - and I am in a different room from AP, probably 4m through wall & furniture.