From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from charlotte.tuxdriver.com ([70.61.120.58]:59374 "EHLO smtp.tuxdriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755735AbZEMSaP (ORCPT ); Wed, 13 May 2009 14:30:15 -0400 Date: Wed, 13 May 2009 14:25:24 -0400 From: "John W. Linville" To: Bob Copeland Cc: forrest@hifulltech.com, ath5k-devel@lists.ath5k.org, mickflemm@gmail.com, jirislaby@gmail.com, lrodriguez@atheros.com, linux-wireless@vger.kernel.org Subject: Re: [PATCH] ath5k: fix exp off-by-one when computing OFDM delta slope Message-ID: <20090513182524.GF2680@tuxdriver.com> References: <20090513151439.GA28476@hash.localnet> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20090513151439.GA28476@hash.localnet> Sender: linux-wireless-owner@vger.kernel.org List-ID: On Wed, May 13, 2009 at 11:14:39AM -0400, Bob Copeland wrote: > > From: Forrest Zhang > > Commit e8f055f0c3ba226ca599c14c2e5fe829f6f57cbb subtly changed the > code that computes floating point values for the PHY3_TIMING register > such that the exponent is off by a decimal point, which can cause > problems with OFDM channel operation. > > get_bitmask_order() actually returns the highest bit set plus one, > whereas the previous code wanted the highest bit set. Instead, use > ilog2 which is what this code is really calculating. Also check > coef_scaled to handle the (invalid) case where we need log2(0). > > Signed-off-by: Bob Copeland > --- > > John, this plus 706d64453cce7179e05924c24d87777584a1275c fixes a > regression for 2.6.30 5ghz operation (bugzilla 13077). Any chance > they can both make it in? I can send a backport of this patch if > you like (usual path change). That's fine. But what about this last bit? http://bugzilla.kernel.org/show_bug.cgi?id=13077#c6 Is that not needed? John -- John W. Linville Someday the world will need a hero, and you linville@tuxdriver.com might be all we have. Be ready.