PM: add kconfig option for deprecated .../power/state files

Add a new PM_SYSFS_DEPRECATED config option to control whether or
not the /sys/devices/.../power/state files are provided.  This will
make it easier to get rid of that mechanism when the time comes,
and to verify that userspace tools work right without it.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Acked-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 11 insertions, 0 deletions

diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig
index 619ecabf7c58..1ed972070d19 100644
--- a/kernel/power/Kconfig
+++ b/kernel/power/Kconfig
@@ -53,6 +53,17 @@ config PM_TRACE
         CAUTION: this option will cause your machine's real-time clock to be
         set to an invalid time after a resume.
 
+config PM_SYSFS_DEPRECATED
+        bool "Driver model /sys/devices/.../power/state files (DEPRECATED)"
+        depends on PM && SYSFS
+        default n
+        help
+          The driver model started out with a sysfs file intended to provide
+          a userspace hook for device power management.  This feature has never
+          worked very well, except for limited testing purposes, and so it will
+          be removed.   It's not clear that a generic mechanism could really
+          handle the wide variability of device power states; any replacements
+          are likely to be bus or driver specific.
 
 config SOFTWARE_SUSPEND
         bool "Software Suspend"