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authorAlan Stern <stern@rowland.harvard.edu>2007-05-30 23:39:33 +0400
committerGreg Kroah-Hartman <gregkh@suse.de>2007-07-13 03:34:30 +0400
commitb41a60eca833d76593d4dac8a59f5c38714194ee (patch)
treea7c5cf721d9978503c3c8c88183747cf954b8733 /Documentation/ABI/testing/sysfs-bus-usb
parent54515fe528d8c6f9bfaf7d0b9fffb908deecad78 (diff)
downloadlinux-b41a60eca833d76593d4dac8a59f5c38714194ee.tar.xz
USB: add power/persist device attribute
This patch (as920) adds an extra level of protection to the USB-Persist facility. Now it will apply by default only to hubs; for all other devices the user must enable it explicitly by setting the power/persist device attribute. The disconnect_all_children() routine in hub.c has been removed and its code placed inline. This is the way it was originally as part of hub_pre_reset(); the revised usage in hub_reset_resume() is sufficiently different that the code can no longer be shared. Likewise, mark_children_for_reset() is now inline as part of hub_reset_resume(). The end result looks much cleaner than before. The sysfs interface is updated to add the new attribute file, and there are corresponding documentation updates. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'Documentation/ABI/testing/sysfs-bus-usb')
-rw-r--r--Documentation/ABI/testing/sysfs-bus-usb13
1 files changed, 13 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-bus-usb b/Documentation/ABI/testing/sysfs-bus-usb
index f9937add033d..9734577d1711 100644
--- a/Documentation/ABI/testing/sysfs-bus-usb
+++ b/Documentation/ABI/testing/sysfs-bus-usb
@@ -39,3 +39,16 @@ Description:
If you want to suspend a device immediately but leave it
free to wake up in response to I/O requests, you should
write "0" to power/autosuspend.
+
+What: /sys/bus/usb/devices/.../power/persist
+Date: May 2007
+KernelVersion: 2.6.23
+Contact: Alan Stern <stern@rowland.harvard.edu>
+Description:
+ If CONFIG_USB_PERSIST is set, then each USB device directory
+ will contain a file named power/persist. The file holds a
+ boolean value (0 or 1) indicating whether or not the
+ "USB-Persist" facility is enabled for the device. Since the
+ facility is inherently dangerous, it is disabled by default
+ for all devices except hubs. For more information, see
+ Documentation/usb/persist.txt.