linux-kernel - RE: [PATCH] ACPI: Move timer broadcast and pmtimer access before C3arbiter shutdown

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Date:	Wed, 6 Jun 2007 14:02:46 -0700
From:	"Pallipadi, Venkatesh" <venkatesh.pallipadi@...el.com>
To:	"Thomas Gleixner" <tglx@...utronix.de>,
	"Andrew Morton" <akpm@...l.org>
Cc:	"Stable Team" <stable@...nel.org>,
	"LKML" <linux-kernel@...r.kernel.org>,
	"Len Brown" <lenb@...nel.org>, "Ingo Molnar" <mingo@...e.hu>,
	"Arjan van de Ven" <arjan@...radead.org>,
	"Andi Kleen" <ak@...e.de>,
	"Udo A. Steinberg" <us15@...inf.tu-dresden.de>,
	"Dave Jones" <davej@...hat.com>
Subject: RE: [PATCH] ACPI: Move timer broadcast and pmtimer access before C3arbiter shutdown


Ack.

Thanks,
Venki 

>-----Original Message-----
>From: Thomas Gleixner [mailto:tglx@...utronix.de] 
>Sent: Wednesday, June 06, 2007 2:38 AM
>To: Andrew Morton
>Cc: Pallipadi, Venkatesh; Stable Team; LKML; Len Brown; Ingo 
>Molnar; Arjan van de Ven; Andi Kleen; Udo A. Steinberg; Dave Jones
>Subject: [PATCH] ACPI: Move timer broadcast and pmtimer access 
>before C3arbiter shutdown
>
>From: Udo A. Steinberg <us15@...inf.tu-dresden.de>
>
>The chip set doc for IHC4 says:
>
>1.In general, software should not attempt any non-posted 
>accesses during
>arbiter disable except to the ICH4's power management registers. This
>implies that interrupt handlers for any unmasked hardware 
>interrupts and
>SMI/NMI should check ARB_DIS status before reading from ICH devices.
>
>So it's not a good idea to access ICH devices after arbiter shut down. 
>
>Signed-off-by: Udo A. Steinberg <us15@...inf.tu-dresden.de>
>Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
>
>---
> drivers/acpi/processor_idle.c |    9 +++++----
> 1 file changed, 5 insertions(+), 4 deletions(-)
>
>Index: linux-2.6.22-rc4/drivers/acpi/processor_idle.c
>===================================================================
>--- linux-2.6.22-rc4.orig/drivers/acpi/processor_idle.c	
>2007-06-06 11:47:21.000000000 +0200
>+++ linux-2.6.22-rc4/drivers/acpi/processor_idle.c	
>2007-06-06 11:48:21.000000000 +0200
>@@ -488,6 +488,11 @@ static void acpi_processor_idle(void)
> 
> 	case ACPI_STATE_C3:
> 
>+		/* Get start time (ticks) */
>+		t1 = inl(acpi_gbl_FADT.xpm_timer_block.address);
>+		/* Handle timer broadcast before bus arbiter 
>shutdown ! */
>+		acpi_state_timer_broadcast(pr, cx, 1);
>+
> 		if (pr->flags.bm_check) {
> 			if (atomic_inc_return(&c3_cpu_count) ==
> 			    num_online_cpus()) {
>@@ -502,10 +507,7 @@ static void acpi_processor_idle(void)
> 			ACPI_FLUSH_CPU_CACHE();
> 		}
> 
>-		/* Get start time (ticks) */
>-		t1 = inl(acpi_gbl_FADT.xpm_timer_block.address);
> 		/* Invoke C3 */
>-		acpi_state_timer_broadcast(pr, cx, 1);
> 		acpi_cstate_enter(cx);
> 		/* Get end time (ticks) */
> 		t2 = inl(acpi_gbl_FADT.xpm_timer_block.address);
>
-
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