From: Andrew Cooper <andrew.cooper3@citrix.com>
Date: Thu, 7 Nov 2013 14:15:28 +0000 (+0100)
Subject: x86/acpi: Warn about multiple HPET tables
X-Git-Tag: archive/raspbian/4.8.0-1+rpi1~1^2~6052
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=a8a8953873063435e3c73739874edbdce5c114dc;p=xen.git

x86/acpi: Warn about multiple HPET tables

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Tim Deegan <tim@xen.org>
---

diff --git a/xen/arch/x86/acpi/boot.c b/xen/arch/x86/acpi/boot.c
index df264233cd..6d7984ffda 100644
--- a/xen/arch/x86/acpi/boot.c
+++ b/xen/arch/x86/acpi/boot.c
@@ -289,6 +289,22 @@ static int __init acpi_parse_hpet(struct acpi_table_header *table)
 		return -1;
 	}
 
+	/*
+	 * Some BIOSes provide multiple HPET tables.  Sometimes this is a BIOS
+	 * bug; the intended way of supporting more than 1 HPET is to use AML
+	 * entries.
+	 *
+	 * If someone finds a real system with two genuine HPET tables, perhaps
+	 * they will be kind and implement support.  Until then however, warn
+	 * that we will ignore subsequent tables.
+	 */
+	if (hpet_address)
+	{
+		printk(KERN_WARNING PREFIX
+		       "Found multiple HPET tables. Only using first\n");
+		return -1;
+	}
+
 	hpet_address = hpet_tbl->address.address;
 	hpet_blockid = hpet_tbl->sequence;
 	printk(KERN_INFO PREFIX "HPET id: %#x base: %#lx\n",