From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ivo van Doorn Subject: Re: Dscape ieee80211: enabling/disabling the radio Date: Wed, 10 May 2006 15:37:11 +0200 Message-ID: <200605101537.15213.IvDoorn@gmail.com> References: <200605061401.01795.IvDoorn@gmail.com> <200605100001.20180.IvDoorn@gmail.com> <200605091836.10138.flamingice@sourmilk.net> Mime-Version: 1.0 Content-Type: multipart/signed; boundary="nextPart1847391.3fMDU7WrJV"; protocol="application/pgp-signature"; micalg=pgp-sha1 Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, Olivier , Jiri Benc Return-path: Received: from nf-out-0910.google.com ([64.233.182.187]:48419 "EHLO nf-out-0910.google.com") by vger.kernel.org with ESMTP id S964959AbWEJNfp (ORCPT ); Wed, 10 May 2006 09:35:45 -0400 Received: by nf-out-0910.google.com with SMTP id p46so1269727nfa for ; Wed, 10 May 2006 06:35:44 -0700 (PDT) To: Michael Wu In-Reply-To: <200605091836.10138.flamingice@sourmilk.net> Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org --nextPart1847391.3fMDU7WrJV Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Content-Disposition: inline On Wednesday 10 May 2006 00:36, Michael Wu wrote: > On Tuesday 09 May 2006 18:01, Ivo van Doorn wrote: > > A user on the forums Olivier Cornu (added to the CC list) has done some > > investigation into the scanning behaviour of the dscape stack. > > Basicly the dscape stack is performing active scanning while the device= is > > down, but during the active scan it is sending packets out, or at least > > attempting to do so. Besides the question if active scanning is preferr= ed > > over passive scanning while interface is down, active scanning fails > > because the packets that should be send are being send through the regu= lar > > xmit routines of the interface. (IFF_UP is not set for the interface) > > > > This means that besides enabling the radio which should be done in the > > driver, the stack should either bring up the interface when doing an ac= tive > > scan, or resort to passive scanning while interface is down. > > > If you can passive scan while the interface is down, I don't think it's r= eally=20 > down. In adm8211, nothing can be sent or received when the interface is d= own.=20 > The radio is always off when the interface is down. Taking the interface = up=20 > just for a scan and then taking it back down doesn't sound too good eithe= r. I=20 > think scans should be prohibited while the interface is down, since leavi= ng=20 > the interface on isn't gonna do anything bad unless you put in the info t= o=20 > associate. True, I agree here. But when rt2x00 was using the ipw stack a much requested feature from users was to be able to perform scanning while interface was down. (The requests did not specify if it they wanted passive= or active scanning) But the reason for these requests was that some user space applications and= /or distribution network scripts relied on the fact that the driver was capable= of scanning while the interface was down, so the interface would only be brought up at = boot time, when there was no desired AP in the scan result. I don't know which distributions or user space application these were, but = due to the amount of these requests it had been considered an important feature. Ivo --nextPart1847391.3fMDU7WrJV Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.2 (GNU/Linux) iD8DBQBEYeyLaqndE37Em0gRAv4OAKDh13S5tOjfuYtNuBo9vudHxG8eSQCfWUmf E4ND8ob0va9JKFcUfrF1f34= =DdsN -----END PGP SIGNATURE----- --nextPart1847391.3fMDU7WrJV--