USB: Allow autosuspend delay to equal 0

This patch (as867) adds an entry for the new power/autosuspend
attribute in Documentation/ABI/testing, and it changes the behavior of
the delay value.  Now a delay of 0 means to autosuspend as soon as
possible, and negative values will prevent autosuspend.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 15 insertions, 0 deletions

diff --git a/Documentation/ABI/testing/sysfs-bus-usb b/Documentation/ABI/testing/sysfs-bus-usb
new file mode 100644
index 000000000000..00a84326325f
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-bus-usb
@@ -0,0 +1,15 @@
+What:           /sys/bus/usb/devices/.../power/autosuspend
+Date:           March 2007
+KernelVersion:  2.6.21
+Contact:        Alan Stern <stern@rowland.harvard.edu>
+Description:
+                Each USB device directory will contain a file named
+                power/autosuspend.  This file holds the time (in seconds)
+                the device must be idle before it will be autosuspended.
+                0 means the device will be autosuspended as soon as
+                possible.  Negative values will prevent the device from
+                being autosuspended at all, and writing a negative value
+                will resume the device if it is already suspended.
+
+                The autosuspend delay for newly-created devices is set to
+                the value of the usbcore.autosuspend module parameter.