Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932611AbWHDMcE (ORCPT ); Fri, 4 Aug 2006 08:32:04 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932613AbWHDMcD (ORCPT ); Fri, 4 Aug 2006 08:32:03 -0400 Received: from 1wt.eu ([62.212.114.60]:25613 "EHLO 1wt.eu") by vger.kernel.org with ESMTP id S932611AbWHDMcB (ORCPT ); Fri, 4 Aug 2006 08:32:01 -0400 Date: Fri, 4 Aug 2006 14:21:55 +0200 From: Willy Tarreau To: Michael Buesch Cc: Jukka Partanen , kkeil@suse.de, linux-kernel@vger.kernel.org, Alan Cox Subject: Re: [PATCH 2.4.32] Fix AVM C4 ISDN card init problems with newer CPUs Message-ID: <20060804122155.GA25727@1wt.eu> References: <1154627776.23655.106.camel@localhost.localdomain> <20060804065623.GA24404@1wt.eu> <200608041239.13260.mb@bu3sch.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200608041239.13260.mb@bu3sch.de> User-Agent: Mutt/1.5.11 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2377 Lines: 66 On Fri, Aug 04, 2006 at 12:39:12PM +0200, Michael Buesch wrote: > On Friday 04 August 2006 08:56, Willy Tarreau wrote: > > On Thu, Aug 03, 2006 at 06:56:15PM +0100, Alan Cox wrote: > > > Ar Iau, 2006-08-03 am 19:53 +0300, ysgrifennodd Jukka Partanen: > > > > 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. > > > > > > Should be using cpu_relax() I think. Its a polled busy loop so you want > > > other CPU threads to run if possible. > > > > You mean like this ? Here's the patch for 2.6, I'll queue the same for 2.4 > > if it's alright. > > > > > Alan > > > > Regards, > > Willy > > > > From 512d12bd7ce9c0a15dfd91a6f7c2970c92b3abdd Mon Sep 17 00:00:00 2001 > > From: Willy Tarreau > > Date: Fri, 4 Aug 2006 08:50:10 +0200 > > Subject: [PATCH] AVM C4 ISDN card : use cpu_relax() in busy loops > > > > As suggested by Alan, use cpu_relax() in 3 busy loops : "It's a > > polled busy loop so you want other CPU threads to run if possible". > > > > Signed-off-by: Willy Tarreau > > --- > > drivers/isdn/hardware/avm/c4.c | 4 ++++ > > 1 files changed, 4 insertions(+), 0 deletions(-) > > > > diff --git a/drivers/isdn/hardware/avm/c4.c b/drivers/isdn/hardware/avm/c4.c > > index f7253b2..aee278e 100644 > > --- a/drivers/isdn/hardware/avm/c4.c > > +++ b/drivers/isdn/hardware/avm/c4.c > > @@ -22,6 +22,7 @@ #include > > #include > > #include > > #include > > +#include > > #include > > #include > > #include > > @@ -150,6 +151,7 @@ static inline int wait_for_doorbell(avmc > > if (!time_before(jiffies, stop)) > > return -1; > > mb(); > > + cpu_relax(); > > cpu_relax() implies a memory barrier. OK fine. Reading from various asm-xxx/processor.h files, I was not sure about this. I will repost it fixed and queue it for next 2.4 too. > Greetings Michael. Thanks, Willy - 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/