ACPI: Make acpi_skip_timer_override cover all source_irq==0 cases

commit ae10ccdc upstream.

Currently when acpi_skip_timer_override is set, it only cover the
(source_irq == 0 && global_irq == 2) cases. While there is also
platform which need use this option and its global_irq is not 2.
This patch will extend acpi_skip_timer_override to cover all
timer overriding cases as long as the source irq is 0.

This is the first part of a fix to kernel bug bugzilla 40002:
	"IRQ 0 assigned to VGA"
https://bugzilla.kernel.org/show_bug.cgi?id=40002Reported-and-tested-by: Szymon Kowalczyk <fazerxlo@o2.pl>
Signed-off-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

arch/x86/kernel/acpi/boot.c

@@ -416,12 +416,14 @@ acpi_parse_int_src_ovr(struct acpi_subtable_header * header,
 		return 0;
 	}
 
-	if (intsrc->source_irq == 0 && intsrc->global_irq == 2) {
+	if (intsrc->source_irq == 0) {
 		if (acpi_skip_timer_override) {
-			printk(PREFIX "BIOS IRQ0 pin2 override ignored.\n");
+			printk(PREFIX "BIOS IRQ0 override ignored.\n");
 			return 0;
 		}
-		if (acpi_fix_pin2_polarity && (intsrc->inti_flags & ACPI_MADT_POLARITY_MASK)) {
+
+		if ((intsrc->global_irq == 2) && acpi_fix_pin2_polarity
+			&& (intsrc->inti_flags & ACPI_MADT_POLARITY_MASK)) {
 			intsrc->inti_flags &= ~ACPI_MADT_POLARITY_MASK;
 			printk(PREFIX "BIOS IRQ0 pin2 override: forcing polarity to high active.\n");
 		}
@@ -1327,7 +1329,7 @@ static int __init dmi_disable_acpi(const struct dmi_system_id *d)
 }
 
 /*
- * Force ignoring BIOS IRQ0 pin2 override
+ * Force ignoring BIOS IRQ0 override
  */
 static int __init dmi_ignore_irq0_timer_override(const struct dmi_system_id *d)
 {
@@ -1337,7 +1339,7 @@ static int __init dmi_ignore_irq0_timer_override(const struct dmi_system_id *d)
 	 */
 	if (!acpi_skip_timer_override) {
 		WARN(1, KERN_ERR "ati_ixp4x0 quirk not complete.\n");
-		pr_notice("%s detected: Ignoring BIOS IRQ0 pin2 override\n",
+		pr_notice("%s detected: Ignoring BIOS IRQ0 override\n",
 			d->ident);
 		acpi_skip_timer_override = 1;
 	}
@@ -1431,7 +1433,7 @@ static struct dmi_system_id __initdata acpi_dmi_table_late[] = {
 	 * is enabled.  This input is incorrectly designated the
 	 * ISA IRQ 0 via an interrupt source override even though
 	 * it is wired to the output of the master 8259A and INTIN0
-	 * is not connected at all.  Force ignoring BIOS IRQ0 pin2
+	 * is not connected at all.  Force ignoring BIOS IRQ0
 	 * override in that cases.
 	 */
 	{