From: Brian Maly <bmaly@redhat.com>
Subject: [RHEL5.1 patch] disable pnpacpi on IBM x460
Date: Wed, 06 Jun 2007 19:23:25 -0400
Bugzilla: 243730
Message-Id: <466741ED.3080708@redhat.com>
Changelog: [misc] disable pnpacpi on IBM x460


Resolves IT# 122915, still waiting for the BZ. This issue came up at the 
last minute.

On the IBM x460, the RTC is sometimes not accessable if "pnpacpi=off" is 
not used at boot.
The problem is due to BIOS buggyness and occurs only when the HPET is 
disabled in the BIOS, and occurs with all timesources. The RTC works 
correctly when the HPET is enabled in the BIOS. This is related to BZ 
220196 which has the same symptoms but have a different cause. To solve 
this problem you need this patch to fix irq issues for RTC, then the 
patch for BZ 220196 to get support HPET legacy replacement mode.

This patch is low risk and simply disables pnpacpi during boot 
automagically on the affected hardware.

This patch was tested and resolves the problem.

Brian



--- linux-2.6.18.noarch/drivers/pnp/pnpacpi/core.c.orig	2007-06-06 17:34:09.000000000 -0400
+++ linux-2.6.18.noarch/drivers/pnp/pnpacpi/core.c	2007-06-06 18:46:28.000000000 -0400
@@ -22,6 +22,7 @@
 #include <linux/acpi.h>
 #include <linux/pnp.h>
 #include <acpi/acpi_bus.h>
+#include <linux/dmi.h>
 #include "pnpacpi.h"
 
 static int num = 0;
@@ -236,10 +237,29 @@ static acpi_status __init pnpacpi_add_de
 	return AE_OK;
 }
 
+static int __init disable_pnpacpi(struct dmi_system_id *d)
+{
+        printk(KERN_WARNING "%s detected. Disabling PnP-ACPI\n", d->ident);
+	pnpacpi_disabled = 1;
+        return 0;
+}
+
+static struct dmi_system_id pnpacpi_dmi_table[] __initdata = {
+        {       /* PnPBIOS GPF on boot */
+                .callback = disable_pnpacpi,
+                .ident = "IBM x460/x3950",
+                .matches = {
+                        DMI_MATCH(DMI_SYS_VENDOR, "IBM"),
+                        DMI_MATCH(DMI_PRODUCT_NAME, "IBM x3950-[88722RU]-"),
+                },
+        },
+        { }
+};
+
 int pnpacpi_disabled __initdata;
 static int __init pnpacpi_init(void)
 {
-	if (acpi_disabled || pnpacpi_disabled) {
+	if (acpi_disabled || pnpacpi_disabled || dmi_check_system(pnpacpi_dmi_table)) {
 		pnp_info("PnP ACPI: disabled");
 		return 0;
 	}