rtc: Disable EFI rtc for x86

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@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: <stable@vger.kernel.org> # v3.17
Signed-off-by: Matt Fleming <matt.fleming@intel.com>

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index a168e96142b95001f5ece9585cfff8a07c1bb489..54ef393b0def14aa415a1789ba3e1ee51c94bc5f 100644 (file)
--- 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.