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From: Ingo Molnar <mingo@elte.hu>
To: Andrew Morton <akpm@osdl.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	LKML <linux-kernel@vger.kernel.org>, Jim Gettys <jg@laptop.org>,
	John Stultz <johnstul@us.ibm.com>,
	David Woodhouse <dwmw2@infradead.org>,
	Arjan van de Ven <arjan@infradead.org>,
	Dave Jones <davej@redhat.com>
Subject: [patch] clockevents: drivers for i386, fix #2
Date: Tue, 3 Oct 2006 12:35:03 +0200	[thread overview]
Message-ID: <20061003103503.GA6350@elte.hu> (raw)
In-Reply-To: <20061003084729.GA24961@elte.hu>


* Ingo Molnar <mingo@elte.hu> wrote:

> yeah, i suspect it works again if you disable:
> 
>  CONFIG_X86_UP_APIC=y
>  CONFIG_X86_UP_IOAPIC=y
>  CONFIG_X86_LOCAL_APIC=y
>  CONFIG_X86_IO_APIC=y
> 
> as the slowdown has the feeling of a runaway lapic timer irq.
> 
> from code review so far we can only see an udelay(10) difference in 
> the initialization sequence of the PIT - we'll send a fix for that but 
> i dont think that's the cause of the bug.

the patch below fixes that particular bug. But ... the symptoms you are 
describing have the feeling of being apic related.

	Ingo

-------------------->
Subject: clockevents: drivers for i386, fix #2
From: Ingo Molnar <mingo@elte.hu>

add back a mistakenly removed udelay(10) to the PIT initialization
sequence.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 arch/i386/kernel/i8253.c |    1 +
 1 file changed, 1 insertion(+)

Index: linux/arch/i386/kernel/i8253.c
===================================================================
--- linux.orig/arch/i386/kernel/i8253.c
+++ linux/arch/i386/kernel/i8253.c
@@ -45,6 +45,7 @@ static void init_pit_timer(enum clock_ev
 		outb_p(0x34, PIT_MODE);
 		udelay(10);
 		outb_p(LATCH & 0xff , PIT_CH0);	/* LSB */
+		udelay(10);
 		outb(LATCH >> 8 , PIT_CH0);	/* MSB */
 		break;
 

  reply	other threads:[~2006-10-03 10:43 UTC|newest]

Thread overview: 58+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-10-01 22:59 [patch 00/21] high resolution timers / dynamic ticks - V2 Thomas Gleixner
2006-10-01 22:59 ` [patch 01/21] GTOD: exponential update_wall_time Thomas Gleixner
2006-10-01 23:00 ` [patch 02/21] GTOD: persistent clock support, core Thomas Gleixner
2006-10-01 23:00 ` [patch 03/21] GTOD: persistent clock support, i386 Thomas Gleixner
2006-10-01 23:00 ` [patch 04/21] time: uninline jiffies.h Thomas Gleixner
2006-10-01 23:00 ` [patch 05/21] time: fix msecs_to_jiffies() bug Thomas Gleixner
2006-10-01 23:00 ` [patch 06/21] time: fix timeout overflow Thomas Gleixner
2006-10-01 23:00 ` [patch 07/21] cleanup: uninline irq_enter() and move it into a function Thomas Gleixner
2006-10-01 23:00 ` [patch 08/21] dynticks: extend next_timer_interrupt() to use a reference jiffie Thomas Gleixner
2006-10-01 23:00 ` [patch 09/21] hrtimers: namespace and enum cleanup Thomas Gleixner
2006-10-01 23:00 ` [patch 10/21] hrtimers: clean up locking Thomas Gleixner
2006-10-01 23:00 ` [patch 11/21] hrtimers: state tracking Thomas Gleixner
2006-10-01 23:00 ` [patch 12/21] hrtimers: clean up callback tracking Thomas Gleixner
2006-10-01 23:01 ` [patch 13/21] hrtimers: Move and add documentation Thomas Gleixner
2006-10-01 23:01 ` [patch 14/21] clockevents: core Thomas Gleixner
2006-10-01 23:01 ` [patch 15/21] clockevents: drivers for i386 Thomas Gleixner
2006-10-01 23:01 ` [patch 16/21] high-res timers: core Thomas Gleixner
2006-10-02 11:50   ` Paulo Marques
2006-10-01 23:01 ` [patch 17/21] dynticks: core Thomas Gleixner
2006-10-02  6:41   ` [patch] dynticks: core, NMI watchdog fix Ingo Molnar
2006-10-02  8:54     ` [patch] dynticks: core, NMI watchdog fix, #2 Ingo Molnar
2006-10-01 23:01 ` [patch 18/21] dyntick: add nohz stats to /proc/stat Thomas Gleixner
2006-10-01 23:01 ` [patch 19/21] dynticks: i386 arch code Thomas Gleixner
2006-10-01 23:01 ` [patch 20/21] high-res timers, dynticks: enable i386 support Thomas Gleixner
2006-10-01 23:01 ` [patch 21/21] debugging feature: timer stats Thomas Gleixner
2006-10-02  5:11 ` [patch 00/21] high resolution timers / dynamic ticks - V2 Valdis.Kletnieks
2006-10-02 13:02 ` Valdis.Kletnieks
2006-10-02 13:43   ` Thomas Gleixner
2006-10-02 18:25     ` Valdis.Kletnieks
2006-10-02 18:38       ` john stultz
2006-10-02 19:08         ` Valdis.Kletnieks
2006-10-02 19:23           ` john stultz
2006-10-02 18:43       ` [patch] dynticks core: Fix idle time accounting Thomas Gleixner
2006-10-02 20:17         ` Valdis.Kletnieks
2006-10-02 21:22           ` Thomas Gleixner
2006-10-02 21:35             ` Valdis.Kletnieks
2006-10-03 20:02               ` Thomas Gleixner
2006-10-03 21:05                 ` Thomas Gleixner
2006-10-04  2:33                 ` Valdis.Kletnieks
2006-10-04  7:56                   ` Ingo Molnar
2006-10-04  9:58                     ` Valdis.Kletnieks
2006-10-03  3:23 ` [patch 00/21] high resolution timers / dynamic ticks - V2 Andrew Morton
2006-10-03  4:00 ` Andrew Morton
2006-10-03  8:38   ` Thomas Gleixner
2006-10-03  8:47   ` Ingo Molnar
2006-10-03 10:35     ` Ingo Molnar [this message]
2006-10-04  3:36       ` [patch] clockevents: drivers for i386, fix #2 Andrew Morton
2006-10-04  6:46         ` Ingo Molnar
2006-10-04  7:32           ` Andrew Morton
2006-10-04  7:41             ` Ingo Molnar
2006-10-04  8:01               ` Andrew Morton
2006-10-04  7:55             ` Ingo Molnar
2006-10-04  8:15               ` Andrew Morton
2006-10-04 10:53                 ` Ingo Molnar
2006-10-04 11:19                   ` Thomas Gleixner
2006-10-04 16:02                     ` Andrew Morton
2006-10-04 16:20                       ` Thomas Gleixner
2006-10-04 16:35                       ` Ingo Molnar

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