From owner-freebsd-net@FreeBSD.ORG Fri May 1 14:20:28 2009 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 24F9A1065675 for ; Fri, 1 May 2009 14:20:28 +0000 (UTC) (envelope-from onemda@gmail.com) Received: from fg-out-1718.google.com (fg-out-1718.google.com [72.14.220.157]) by mx1.freebsd.org (Postfix) with ESMTP id AAC788FC21 for ; Fri, 1 May 2009 14:20:27 +0000 (UTC) (envelope-from onemda@gmail.com) Received: by fg-out-1718.google.com with SMTP id l26so699701fgb.12 for ; Fri, 01 May 2009 07:20:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:in-reply-to:references :date:message-id:subject:from:to:cc:content-type :content-transfer-encoding; bh=ZWH2hjQr53fDEGgnp+BiER0bSYkoFUCQwS8l/eEWGvA=; b=bXO85pNlTbb0RjZR6+QD+mmL/ZlzU0K0YLDNo8Ptv4/RfefNgj9sod3pLiluUor1W0 o5om+BGZrLl+UmhbzbGY8loUH9+vTmi34u47s0Prf2mHU9iZKKt871aYPn0N/i86J1wC OG+ZYS2XewMTunlB0xguZe19mO4LafaDlNt78= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=jv4Fcmqu0XG4qB1tvOJzvZVftNTN8D1B89Awa1yyEOtwuYdmQNkWi/7v86w2dXRAXB ZTTVdDQVPLAdkInqJ8uXb5uqu23FmbpWEMd4DpcDy1rGNtivJxC1pbbqFxcC/eAAT8IF hbe1HPqhit35pFGComJ/yNr/G4bcUjpXQ4egg= MIME-Version: 1.0 Received: by 10.239.163.69 with SMTP id o5mr143520hbd.40.1241186153128; Fri, 01 May 2009 06:55:53 -0700 (PDT) In-Reply-To: <49FA2E3F.9050108@entel.upc.edu> References: <49FA2E3F.9050108@entel.upc.edu> Date: Fri, 1 May 2009 15:55:53 +0200 Message-ID: <3a142e750905010655i5e56282eu240e13f2a03dfb02@mail.gmail.com> From: "Paul B. Mahol" To: Gustau Perez Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: freebsd-net@freebsd.org Subject: Re: Signal sensitivity problem with if_rum X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 01 May 2009 14:20:28 -0000 On 5/1/09, Gustau Perez wrote: > > Hi, > > I think this is right place to post, if it is not, please let me know. > > I'm experiencing problems with two different devices using if_rum. > One is a Hercules Guillemot and the other is a Linksys Cisco WUSB54GC > > The first one is about sensitivity, which is very low: for example, > I'm detecting just two or three networks around me (with windows both > usb devices detect around 14 or 15 networks) and the reported signal is > very low.Placing the sensor very near to my wireless network AP (which > is a FreeBSD machine with atheros card placing the txpower to 20) > reports a signal quality of 50% or 60%. > > Linux presents the same problem (my wife's laptop with ubuntu shows > the same figures, more or > > The other one is that having such a low sensitivity makes those > dongles unusable when making large transfers, mostly when using scp/sftp > or sshfs (samba seems to make it work better for longer transfer, but > finally the problem appears). At some given point, the dongles seem to > lose contact with the AP (making ifconfig shows that wlan0 is still > associated), waiting for a period of time (usually one or two minutes) > the transfer continues. Probably both problems are related. > > In order to debug the problem I tried looking dmesg in both my AP and > my laptop (no trace). Tried looking at the ssh logs (when making large > transfers, no clue). In the only place I found something was in the > samba logs, only saying that there was a problem with the transfer > (broken pipe, the socket is closed). > > So : > > In the linux world, I found that the register which controls the > sensitivity is bbp17 : > > http://209.85.229.132/search?q=cache:H8W6R5Ds3mYJ:forum.aircrack-ng.org/index.php%3Ftopic%3D2235.0+bbp17+ralink+linux&cd=1&hl=ca&ct=clnk&gl=es&client=firefox-a > > Tried looking in > /usr/src/sys/dev/usb/wlan/if_rum.c, but I got lost. Tried with sysctl -a > | grep rum or grep wlan0, but no MiB related to sensitivity appeared. > > Is there anything I can try ? How can I force bbp 17 to get 0 value ? > Tried with rum_def_bbp in if_rum.c, changing 17 to 0. No luck. There is several places where bbp17 is changed. Last time I was exploring rum I found that it lacks bbp auto tuning. [Failed to implement it, because in meantime I broke chip :)] -- Paul