[PATCH 3.17 177/319] rtc: Disable EFI rtc for x86

[Greg Kroah-Hartman]

3.17-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Matt Fleming <matt.fleming@xxxxxxxxx>

commit 7efe665903d0d963b0ebf4cab25cc3ae32c62600 upstream.

commit da167ad7638759 ("rtc: ia64: allow other architectures to use EFI
RTC") inadvertently introduced a regression for x86 because we've been
careful not to enable the EFI rtc driver due to the generally buggy
implementations of the time-related EFI runtime services.

In fact, since the above commit was merged we've seen reports of crashes
on 32-bit tablets,

  https://bugzilla.kernel.org/show_bug.cgi?id=84241#c21

Disable it explicitly for x86 so that we don't give users false hope
that this driver will work - it won't, and your machine is likely to
crash.

Acked-by: Mark Salter <msalter@xxxxxxxxxx>
Cc: Dave Young <dyoung@xxxxxxxxxx>
Cc: Alessandro Zummo <a.zummo@xxxxxxxxxxxx>
Signed-off-by: Matt Fleming <matt.fleming@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/rtc/Kconfig |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -806,7 +806,7 @@ config RTC_DRV_DA9063
 
 config RTC_DRV_EFI
 	tristate "EFI RTC"
-	depends on EFI
+	depends on EFI && !X86
 	help
 	  If you say yes here you will get support for the EFI
 	  Real Time Clock.


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