[PATCH] Add kernel<->userspace ABI stability documentation
Signed-off-by: Kay Sievers <kay.sievers@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/Documentation/ABI/testing/sysfs-devices b/Documentation/ABI/testing/sysfs-devices
new file mode 100644
index 0000000..6a25671
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-devices
@@ -0,0 +1,25 @@
+What: /sys/devices
+Date: February 2006
+Contact: Greg Kroah-Hartman <gregkh@suse.de>
+Description:
+ The /sys/devices tree contains a snapshot of the
+ internal state of the kernel device tree. Devices will
+ be added and removed dynamically as the machine runs,
+ and between different kernel versions, the layout of the
+ devices within this tree will change.
+
+ Please do not rely on the format of this tree because of
+ this. If a program wishes to find different things in
+ the tree, please use the /sys/class structure and rely
+ on the symlinks there to point to the proper location
+ within the /sys/devices tree of the individual devices.
+ Or rely on the uevent messages to notify programs of
+ devices being added and removed from this tree to find
+ the location of those devices.
+
+ Note that sometimes not all devices along the directory
+ chain will have emitted uevent messages, so userspace
+ programs must be able to handle such occurrences.
+
+Users:
+ udev <linux-hotplug-devel@lists.sourceforge.net>
