USB: add USB-Persist facility
This patch (as886) adds the controversial USB-persist facility,
allowing USB devices to persist across a power loss during system
suspend.
The facility is controlled by a new Kconfig option (with appropriate
warnings about the potential dangers); when the option is off the
behavior will remain the same as it is now. But when the option is
on, people will be able to use suspend-to-disk and keep their USB
filesystems intact -- something particularly valuable for small
machines where the root filesystem is on a USB device!
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/include/linux/usb.h b/include/linux/usb.h
index 56aa2ee..3d63e0c 100644
--- a/include/linux/usb.h
+++ b/include/linux/usb.h
@@ -403,6 +403,7 @@
unsigned auto_pm:1; /* autosuspend/resume in progress */
unsigned do_remote_wakeup:1; /* remote wakeup should be enabled */
+ unsigned reset_resume:1; /* needs reset instead of resume */
unsigned autosuspend_disabled:1; /* autosuspend and autoresume */
unsigned autoresume_disabled:1; /* disabled by the user */
#endif
@@ -819,7 +820,10 @@
* @pre_reset: Called by usb_reset_composite_device() when the device
* is about to be reset.
* @post_reset: Called by usb_reset_composite_device() after the device
- * has been reset.
+ * has been reset, or in lieu of @resume following a reset-resume
+ * (i.e., the device is reset instead of being resumed, as might
+ * happen if power was lost). The second argument tells which is
+ * the reason.
* @id_table: USB drivers use ID table to support hotplugging.
* Export this with MODULE_DEVICE_TABLE(usb,...). This must be set
* or your driver's probe function will never get called.
@@ -861,7 +865,7 @@
int (*resume) (struct usb_interface *intf);
void (*pre_reset) (struct usb_interface *intf);
- void (*post_reset) (struct usb_interface *intf);
+ void (*post_reset) (struct usb_interface *intf, int reset_resume);
const struct usb_device_id *id_table;