Return-path: Received: from he.sipsolutions.net ([78.46.109.217]:44311 "EHLO sipsolutions.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751400Ab2FIIJM (ORCPT ); Sat, 9 Jun 2012 04:09:12 -0400 Message-ID: <1339229344.4539.7.camel@jlt3.sipsolutions.net> (sfid-20120609_100921_479961_0FFBE125) Subject: Re: [RFC 1/2] nl80211: specify RSSI threshold when scanning From: Johannes Berg To: "Pedersen, Thomas" Cc: Kalle Valo , linux-wireless@vger.kernel.org, ath6kl-devel@qualcomm.com Date: Sat, 09 Jun 2012 10:09:04 +0200 In-Reply-To: <20120607191803.GA4323@pista> References: <1339036996-6199-1-git-send-email-c_tpeder@qca.qualcomm.com> <4FD0570D.50303@qca.qualcomm.com> <20120607183820.GA2950@pista> <4FD0F8A0.3000704@qca.qualcomm.com> <20120607191803.GA4323@pista> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Sender: linux-wireless-owner@vger.kernel.org List-ID: On Thu, 2012-06-07 at 12:18 -0700, Pedersen, Thomas wrote: > On Thu, Jun 07, 2012 at 09:53:20PM +0300, Kalle Valo wrote: > > On 06/07/2012 09:38 PM, Pedersen, Thomas wrote: > > >>> + WIPHY_FLAG_SUPPORTS_RSSI_SCAN = BIT(22), > > >>> > > }; > > >> > > > >> > Is this flag really needed? For me this looks like an optimisation more > > >> > than a functional change. If the driver supports this, that's great and > > >> > we can save some power. But if the driver does not support it does it > > >> > really make any difference for the user space? Would user space act > > >> > differently if this feature is not supported by the driver? > > > > > > Well, this allows cfg80211 to return an error if this feature is > > > requested but not supported by the driver / fw. > > > > But do we want to return an error when the driver doesn't support this? > > I was thinking that driver should just ignore the attribute in that case > > and let user space filter the results. > > > > Kalle > > Sure, we can just let userspace unconditionally filter the results when > we do something like: > > iw wlan0 scan rssi -40 > > Johannes, does this look OK to you? I don't see a need to filter in iw, but I agree with Kalle that we shouldn't impose any restrictions on a performance optimisation. johannes