Messages in this thread Patch in this message | | | Date | Fri, 4 Aug 2006 08:56:23 +0200 | From | Willy Tarreau <> | Subject | Re: [PATCH 2.4.32] Fix AVM C4 ISDN card init problems with newer CPUs |
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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 <w@1wt.eu> 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 <w@1wt.eu> --- 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 <linux/capi.h> #include <linux/kernelcapi.h> #include <linux/init.h> #include <asm/io.h> +#include <asm/processor.h> #include <asm/uaccess.h> #include <linux/netdevice.h> #include <linux/isdn/capicmd.h> @@ -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/
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