Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161120AbWHDJlY (ORCPT ); Fri, 4 Aug 2006 05:41:24 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030321AbWHDJlX (ORCPT ); Fri, 4 Aug 2006 05:41:23 -0400 Received: from outpipe-village-512-1.bc.nu ([81.2.110.250]:39054 "EHLO lxorguk.ukuu.org.uk") by vger.kernel.org with ESMTP id S1030300AbWHDJlX (ORCPT ); Fri, 4 Aug 2006 05:41:23 -0400 Subject: Re: [PATCH 2.4.32] Fix AVM C4 ISDN card init problems with newer CPUs From: Alan Cox To: Karsten Keil Cc: Jukka Partanen , linux-kernel@vger.kernel.org In-Reply-To: <20060803173104.GA22317@pingi.kke.suse.de> References: <20060803173104.GA22317@pingi.kke.suse.de> Content-Type: text/plain Content-Transfer-Encoding: 7bit Date: Fri, 04 Aug 2006 11:00:46 +0100 Message-Id: <1154685646.23655.185.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.6.2 (2.6.2-1.fc5.5) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1222 Lines: 38 Ar Iau, 2006-08-03 am 19:31 +0200, ysgrifennodd Karsten Keil: > Yes, that should be go in. > > AVM C4 ISDN NIC: Add three memory barriers, taken from 2.6.7, > (they are there in 2.6.17.7 too), to fix module initialization > problems appearing with at least some newer Celerons and > Pentium III. > > Acked-by: Karsten Keil > Signed-off-by: Jukka Partanen NAK: Alan Cox Two reasons #1 You should use cpu_relax in such loops #2 The readl (which c4inmeml is a pointless #define of) is defined to be a volatile reference itself That means that the real bug would appear to be different and either you have a gcc bug which is possible or you have something stranger going on, such as the continued polling busying the microcontroller the other end, in which case you need a delay not the lucky chance that mb() is slowish on some x86 systems. So you either want cpu_relax + other fixes or udelay(something) Alan - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/