ACPI: blacklist win8 OSI for ASUS Zenbook Prime UX31A

felipec · rafaeljw · commit cb7a386c6c25 · 2013-08-04T16:17:09.000+02:00
Since v3.7 the ACPI backlight driver doesn't work at all on this machine, because presumably the backlight AML code in the ACPI tables contains a code path that triggers when the OS identifies itself as compatible with Windows 8 (which the kernel started to do in 3.7). That code path is never used by Windows and on this particular machine it turns out to be unusable at all. Work around this problem by blacklisting the win8 OSI, so we are back to v3.6 behavior (that is, we don't tell the BIOS that we are compatible with Windows 8). Since v3.7, users have been forced to work around the initial regression by modifying the boot arguments [1]. [1] https://wiki.archlinux.org/index.php/ASUS_Zenbook_Prime_UX31A [rjw: Changelog] Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
diff --git a/drivers/acpi/blacklist.c b/drivers/acpi/blacklist.c
@@ -192,6 +192,12 @@ static int __init dmi_disable_osi_win7(const struct dmi_system_id *d)
 	acpi_osi_setup("!Windows 2009");
 	return 0;
 }
+static int __init dmi_disable_osi_win8(const struct dmi_system_id *d)
+{
+	printk(KERN_NOTICE PREFIX "DMI detected: %s\n", d->ident);
+	acpi_osi_setup("!Windows 2012");
+	return 0;
+}
 
 static struct dmi_system_id acpi_osi_dmi_table[] __initdata = {
 	{
@@ -267,6 +273,14 @@ static struct dmi_system_id acpi_osi_dmi_table[] __initdata = {
 		     DMI_MATCH(DMI_PRODUCT_NAME, "Satellite P305D"),
 		},
 	},
+	{
+	.callback = dmi_disable_osi_win8,
+	.ident = "ASUS Zenbook Prime UX31A",
+	.matches = {
+		     DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
+		     DMI_MATCH(DMI_PRODUCT_NAME, "UX31A"),
+		},
+	},
 
 	/*
 	 * BIOS invocation of _OSI(Linux) is almost always a BIOS bug.
