From 667f36e61198cb5f3397c27b1598fe7d51781185 Mon Sep 17 00:00:00 2001
From: Andy Currid <ACurrid@nvidia.com>
Date: Thu, 8 Jun 2006 00:43:39 -0700
Subject: [PATCH] --- yaml --- r: 27155 b: refs/heads/master c:
 a2ef3a50f19f64d350bdc0aa15c31ae4b8973f57 h: refs/heads/master i:   27153:
 070b6056988f163cf7b27a37adfc05dfc58a8a53   27151:
 98fe6257a02bae15e05a5daf2cabb39c747e145c v: v3

---
 [refs]                             |  2 +-
 trunk/arch/x86_64/kernel/io_apic.c | 30 +++++++++++++++++++++++++-----
 2 files changed, 26 insertions(+), 6 deletions(-)

diff --git a/[refs] b/[refs]
index 5f5661d9328f..e00a6493f22c 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: d44647b0a6e48d18a1402dfa9052d85c4fe98341
+refs/heads/master: a2ef3a50f19f64d350bdc0aa15c31ae4b8973f57
diff --git a/trunk/arch/x86_64/kernel/io_apic.c b/trunk/arch/x86_64/kernel/io_apic.c
index 0de3ea938830..9cc7031b7151 100644
--- a/trunk/arch/x86_64/kernel/io_apic.c
+++ b/trunk/arch/x86_64/kernel/io_apic.c
@@ -271,6 +271,18 @@ __setup("enable_8254_timer", setup_enable_8254_timer);
 #include <linux/pci_ids.h>
 #include <linux/pci.h>
 
+
+#ifdef CONFIG_ACPI
+
+static int nvidia_hpet_detected __initdata;
+
+static int __init nvidia_hpet_check(unsigned long phys, unsigned long size)
+{
+	nvidia_hpet_detected = 1;
+	return 0;
+}
+#endif
+
 /* Temporary Hack. Nvidia and VIA boards currently only work with IO-APIC
    off. Check for an Nvidia or VIA PCI bridge and turn it off.
    Use pci direct infrastructure because this runs before the PCI subsystem. 
@@ -317,11 +329,19 @@ void __init check_ioapic(void)
 					return;
 				case PCI_VENDOR_ID_NVIDIA:
 #ifdef CONFIG_ACPI
-					/* All timer overrides on Nvidia
-				           seem to be wrong. Skip them. */
-					acpi_skip_timer_override = 1;
-					printk(KERN_INFO 
-	     "Nvidia board detected. Ignoring ACPI timer override.\n");
+					/*
+					 * All timer overrides on Nvidia are
+					 * wrong unless HPET is enabled.
+					 */
+					nvidia_hpet_detected = 0;
+					acpi_table_parse(ACPI_HPET,
+							nvidia_hpet_check);
+					if (nvidia_hpet_detected == 0) {
+						acpi_skip_timer_override = 1;
+						printk(KERN_INFO "Nvidia board "
+						    "detected. Ignoring ACPI "
+						    "timer override.\n");
+					}
 #endif
 					/* RED-PEN skip them on mptables too? */
 					return;