edd: add default mode CONFIG_EDD_OFF=n, override with edd={on,off}

Add a kernel parameter option to 'edd' to enable/disable BIOS Enhanced Disk
Drive Services.  CONFIG_EDD_OFF disables EDD while still compiling EDD into
the kernel.  Default behavior can be forced using 'edd=on' or 'edd=off' as
a kernel parameter.

[akpm@linux-foundation.org: fix kernel-parameters.txt]
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Matt Domsch <Matt_Domsch@dell.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "Randy.Dunlap" <rdunlap@xenotime.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 9 insertions, 0 deletions

diff --git a/drivers/firmware/Kconfig b/drivers/firmware/Kconfig
index 40ffd767647d..dc2cec6127d1 100644
--- a/drivers/firmware/Kconfig
+++ b/drivers/firmware/Kconfig
@@ -17,6 +17,15 @@ config EDD
           obscure configurations. Most disk controller BIOS vendors do
           not yet implement this feature.
 
+config EDD_OFF
+        bool "Sets default behavior for EDD detection to off"
+        depends on EDD
+        default n
+        help
+          Say Y if you want EDD disabled by default, even though it is compiled into the
+          kernel. Say N if you want EDD enabled by default. EDD can be dynamically set
+          using the kernel parameter 'edd={on|skipmbr|off}'.
+
 config EFI_VARS
         tristate "EFI Variable Support via sysfs"
         depends on EFI