[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>

1 files changed, 25 insertions, 0 deletions

diff --git a/Documentation/ABI/testing/sysfs-devices b/Documentation/ABI/testing/sysfs-devices
new file mode 100644
index 000000000000..6a25671ee5f6
--- /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>