Return-path: Received: from crystal.sipsolutions.net ([195.210.38.204]:60813 "EHLO sipsolutions.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752565AbXHVJZv (ORCPT ); Wed, 22 Aug 2007 05:25:51 -0400 Subject: b43 vs. the TIM (was: mac80211 AP mode powersaving problems?) From: Johannes Berg To: Kalle Valo Cc: linux-wireless , Jiri Benc , Michael Wu , Michael Buesch In-Reply-To: <87lkccf30m.fsf@tikku.osso.net> References: <1186990509.27916.38.camel@johannes.berg> <87lkccf30m.fsf@tikku.osso.net> Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="=-f21s/rueM5lU/d0neY6n" Date: Wed, 22 Aug 2007 09:49:05 +0200 Message-Id: <1187768945.9267.12.camel@johannes.berg> Mime-Version: 1.0 Sender: linux-wireless-owner@vger.kernel.org List-ID: --=-f21s/rueM5lU/d0neY6n Content-Type: text/plain Content-Transfer-Encoding: quoted-printable On Thu, 2007-08-16 at 08:43 +0300, Kalle Valo wrote: > One thing which came to my mind is that when Nokia 770 is in PSM it > uses PS-Poll to fetch the frames from AP. Few devices do that, so I > wonder if mac80211 supports that properly? I had to return the N770 I tested with to its owner, but I think I found the problem anyway. b43 doesn't have a set_tim() handler so the TIM bits are never set. Michael, the firmware automatically sets the DTIM count field in the beacon according to the the B43_SHM_SH_DTIMPER value, B43_SHM_SH_TIMBPOS must point to the correct offset into the beacon (to the TIM information element.) Bit 0 of the TIM (broadcast/multicast) is set according to whether FIFO 4 has contents or not so we'll have to do some more reverse engineering to get that bit properly set. The microcode doesn't seem to do any other things with the TIM, but I haven't fully understood the PMQ thing yet, but it appears to be just some firmware-assisted PS mode tracking (it adds entries when a STA enters or leaves PS mode or disassociates/deauthenticates etc. johannes --=-f21s/rueM5lU/d0neY6n Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Comment: Johannes Berg (powerbook) iD8DBQBGy+px/ETPhpq3jKURArT5AJ48eN2yuI2vUo0D3+VzAukgrggoEgCgsUX9 xy0F9MqMhdpzrQ8qS+xopaY= =UNWo -----END PGP SIGNATURE----- --=-f21s/rueM5lU/d0neY6n--