Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161073AbWHDHGK (ORCPT ); Fri, 4 Aug 2006 03:06:10 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1161075AbWHDHGK (ORCPT ); Fri, 4 Aug 2006 03:06:10 -0400 Received: from 1wt.eu ([62.212.114.60]:23565 "EHLO 1wt.eu") by vger.kernel.org with ESMTP id S1161073AbWHDHGI (ORCPT ); Fri, 4 Aug 2006 03:06:08 -0400 Date: Fri, 4 Aug 2006 08:56:23 +0200 From: Willy Tarreau To: Alan Cox Cc: Jukka Partanen , kkeil@suse.de, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2.4.32] Fix AVM C4 ISDN card init problems with newer CPUs Message-ID: <20060804065623.GA24404@1wt.eu> References: <1154627776.23655.106.camel@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1154627776.23655.106.camel@localhost.localdomain> User-Agent: Mutt/1.5.11 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2289 Lines: 75 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(); } return 0; } @@ -303,6 +305,7 @@ static void c4_reset(avmcard *card) return; c4outmeml(card->mbase+DOORBELL, DBELL_ADDR); mb(); + cpu_relax(); } c4_poke(card, DC21285_ARMCSR_BASE + CHAN_1_CONTROL, 0); @@ -327,6 +330,7 @@ static int c4_detect(avmcard *card) return 2; c4outmeml(card->mbase+DOORBELL, DBELL_ADDR); mb(); + cpu_relax(); } c4_poke(card, DC21285_ARMCSR_BASE + CHAN_1_CONTROL, 0); -- 1.4.1 - 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/