From b41a60eca833d76593d4dac8a59f5c38714194ee Mon Sep 17 00:00:00 2001 From: Alan Stern Date: Wed, 30 May 2007 15:39:33 -0400 Subject: 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 Signed-off-by: Greg Kroah-Hartman --- Documentation/ABI/testing/sysfs-bus-usb | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'Documentation/ABI/testing/sysfs-bus-usb') 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 +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. -- cgit v1.2.3