linux-kernel - [PATCH] ACPI: Move timer broadcast and pmtimer access before C3 arbiter shutdown

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Date:	Wed, 06 Jun 2007 11:37:53 +0200
From:	Thomas Gleixner <tglx@...utronix.de>
To:	Andrew Morton <akpm@...l.org>
Cc:	Venkatesh Pallipadi <venkatesh.pallipadi@...el.com>,
	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: [PATCH] ACPI: Move timer broadcast and pmtimer access before C3
	arbiter 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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