From: Carlos Corbacho <carlos@strangeworlds.co.uk>

Date: Sat, 26 Dec 2009 19:14:59 +0000 (+0000)

Subject: ACPI: WMI: Survive BIOS with duplicate GUIDs

X-Git-Url: http://git.kernel.org/?p=linux%2Fkernel%2Fgit%2Ftorvalds%2Flinux-2.6.git;a=commitdiff_plain;h=d1f9e4970742bb1e22d07b01bd44f9c357d25c42

ACPI: WMI: Survive BIOS with duplicate GUIDs

It would appear that in BIOS's with nVidia hooks, the GUID

05901221-D566-11D1-B2F0-00A0C9062910 is duplicated. For now, the simplest

solution is to just ignore any duplicate GUIDs. These particular hooks are not

currently supported/ used in the kernel, so whoever does that can figure out

what the 'right' solution should be (if there's a better one).

http://bugzilla.kernel.org/show_bug.cgi?id=14846

Signed-off-by: Carlos Corbacho <carlos@strangeworlds.co.uk>

Reported-by: Larry Finger <Larry.Finger@lwfinger.net>

Reported-by: Oldřich Jedlička <oldium.pro@seznam.cz>

Signed-off-by: Len Brown <len.brown@intel.com>

---

diff --git a/drivers/platform/x86/wmi.c b/drivers/platform/x86/wmi.c

index cc9ad74..b104302 100644

--- a/drivers/platform/x86/wmi.c

+++ b/drivers/platform/x86/wmi.c

@@ -714,6 +714,22 @@ static int wmi_class_init(void)

 	return ret;

 }

+static bool guid_already_parsed(const char *guid_string)

+{

+	struct guid_block *gblock;

+	struct wmi_block *wblock;

+	struct list_head *p;

+

+	list_for_each(p, &wmi_blocks.list) {

+		wblock = list_entry(p, struct wmi_block, list);

+		gblock = &wblock->gblock;

+

+		if (strncmp(gblock->guid, guid_string, 16) == 0)

+			return true;

+	}

+	return false;

+}

+

 /*

  * Parse the _WDG method for the GUID data blocks

  */

@@ -723,6 +739,7 @@ static __init acpi_status parse_wdg(acpi_handle handle)

 	union acpi_object *obj;

 	struct guid_block *gblock;

 	struct wmi_block *wblock;

+	char guid_string[37];

 	acpi_status status;

 	u32 i, total;

@@ -745,6 +762,19 @@ static __init acpi_status parse_wdg(acpi_handle handle)

 	memcpy(gblock, obj->buffer.pointer, obj->buffer.length);

 	for (i = 0; i < total; i++) {

+		/*

+		  Some WMI devices, like those for nVidia hooks, have a

+		  duplicate GUID. It's not clear what we should do in this

+		  case yet, so for now, we'll just ignore the duplicate.

+		  Anyone who wants to add support for that device can come

+		  up with a better workaround for the mess then.

+		*/

+		if (guid_already_parsed(gblock[i].guid) == true) {

+			wmi_gtoa(gblock[i].guid, guid_string);

+			printk(KERN_INFO PREFIX "Skipping duplicate GUID %s\n",

+				guid_string);

+			continue;

+		}

 		wblock = kzalloc(sizeof(struct wmi_block), GFP_KERNEL);

 		if (!wblock)

 			return AE_NO_MEMORY;