samsung-laptop: Disable on EFI hardware
It has been reported that running this driver on some Samsung laptops
with EFI can cause those machines to become bricked as detailed in the
following report,
https://bugs.launchpad.net/ubuntu-cdimage/+bug/1040557
There have also been reports of this driver causing Machine Check
Exceptions on recent EFI-enabled Samsung laptops,
https://bugzilla.kernel.org/show_bug.cgi?id=47121
So disable it if booting from EFI since this driver relies on
grovelling around in the BIOS memory map which isn't going to work.
Cc: Corentin Chary <corentincj@iksaif.net>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Colin Ian King <colin.king@canonical.com>
Cc: Steve Langasek <steve.langasek@canonical.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
diff --git a/drivers/platform/x86/samsung-laptop.c b/drivers/platform/x86/samsung-laptop.c
index 71623a2..d1f03005 100644
--- a/drivers/platform/x86/samsung-laptop.c
+++ b/drivers/platform/x86/samsung-laptop.c
@@ -26,6 +26,7 @@
#include <linux/seq_file.h>
#include <linux/debugfs.h>
#include <linux/ctype.h>
+#include <linux/efi.h>
#include <acpi/video.h>
/*
@@ -1544,6 +1545,9 @@
struct samsung_laptop *samsung;
int ret;
+ if (efi_enabled(EFI_BOOT))
+ return -ENODEV;
+
quirks = &samsung_unknown;
if (!force && !dmi_check_system(samsung_dmi_table))
return -ENODEV;