[PATCH 2/2] samsung-laptop: Disable on EFI hardware

[Matt Fleming <matt@console-pimps.org>]

From: Matt Fleming <matt.fleming@intel.com>

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.

Acked-by: H. Peter Anvin <hpa@zytor.com>
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: platform-driver-x86@vger.kernel.org
Cc: stable@vger.kernel.org
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
---
 drivers/platform/x86/samsung-laptop.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/platform/x86/samsung-laptop.c b/drivers/platform/x86/samsung-laptop.c
index dd90d15..a94c0ee 100644
--- a/drivers/platform/x86/samsung-laptop.c
+++ b/drivers/platform/x86/samsung-laptop.c
@@ -1534,6 +1534,9 @@ static int __init samsung_init(void)
 	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;
-- 
1.7.11.7