ACPI: Add Thinkpad T400, T500 to OSI(Linux) white-list

acpi_osi=Linux helps the mute button work properly by sending Linux
a mute key press.

http://bugzilla.kernel.org/show_bug.cgi?id=13934

Signed-off-by: Jerone Young <jerone.young@canonical.com>
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/acpi/blacklist.c

@@ -224,6 +224,7 @@ static struct dmi_system_id acpi_osi_dmi_table[] __initdata = {
 	 * _OSI(Linux) helps sound
 	 * DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad R61"),
 	 * DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad T61"),
+	 * T400, T500
 	 * _OSI(Linux) has Linux specific hooks
 	 * DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad X61"),
 	 * _OSI(Linux) is a NOP:
@@ -254,6 +255,22 @@ static struct dmi_system_id acpi_osi_dmi_table[] __initdata = {
 		     DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad X61"),
 		},
 	},
+	{
+	.callback = dmi_enable_osi_linux,
+	.ident = "Lenovo ThinkPad T400",
+	.matches = {
+		     DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
+		     DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad T400"),
+		},
+	},
+	{
+	.callback = dmi_enable_osi_linux,
+	.ident = "Lenovo ThinkPad T500",
+	.matches = {
+		     DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
+		     DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad T500"),
+		},
+	},
 	{}
 };