From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-bw0-f46.google.com ([209.85.214.46]:32957 "EHLO mail-bw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753170Ab0GBSVf (ORCPT ); Fri, 2 Jul 2010 14:21:35 -0400 Received: by bwz1 with SMTP id 1so1745906bwz.19 for ; Fri, 02 Jul 2010 11:21:34 -0700 (PDT) From: Helmut Schaa To: Johannes Berg Subject: Re: rt2x00 & mac80211: correct usage of ieee80211_beacon_get_tim? Date: Fri, 2 Jul 2010 20:20:57 +0200 Cc: linux-wireless@vger.kernel.org, Ivo van Doorn , Gertjan van Wingerde References: <201006241521.47623.helmut.schaa@googlemail.com> <201007021959.45704.helmut.schaa@googlemail.com> <1278093964.15412.24.camel@jlt3.sipsolutions.net> In-Reply-To: <1278093964.15412.24.camel@jlt3.sipsolutions.net> MIME-Version: 1.0 Content-Type: Text/Plain; charset="us-ascii" Message-Id: <201007022020.57398.helmut.schaa@googlemail.com> Sender: linux-wireless-owner@vger.kernel.org List-ID: Am Freitag 02 Juli 2010 schrieb Johannes Berg: > On Fri, 2010-07-02 at 19:59 +0200, Helmut Schaa wrote: > > > > unless your > > > device itself is capable of generating the TIM IE _right before_ the > > > beacon gets transmitted. > > > > Agreed. At least on rt2800 we can use the pre tbtt interrupt to update the > > beacon just before it is sent out. > > Careful though. You don't know how far in advance it is triggered (or > maybe you do) or if the time will be sufficient to generate and upload > the beacon to the device. You could even hit lock contention I think. Yeah, the delay is configurable. And yes, we cannot be 100% sure but I already did some tests and on my MIPS board anything >1ms was enough to generate + upload a new beacon to the device. And we can still increase that to a safe default of maybe 5ms or so. Helmut