diff options
| -rw-r--r-- | Documentation/usb/callbacks.txt | 8 | ||||
| -rw-r--r-- | include/linux/usb.h | 6 |
2 files changed, 9 insertions, 5 deletions
diff --git a/Documentation/usb/callbacks.txt b/Documentation/usb/callbacks.txt index bfb36b34b79e..9e85846bdb98 100644 --- a/Documentation/usb/callbacks.txt +++ b/Documentation/usb/callbacks.txt @@ -95,9 +95,11 @@ pre_reset int (*pre_reset)(struct usb_interface *intf); -Another driver or user space is triggering a reset on the device which -contains the interface passed as an argument. Cease IO and save any -device state you need to restore. +A driver or user space is triggering a reset on the device which +contains the interface passed as an argument. Cease IO, wait for all +outstanding URBs to complete, and save any device state you need to +restore. No more URBs may be submitted until the post_reset method +is called. If you need to allocate memory here, use GFP_NOIO or GFP_ATOMIC, if you are in atomic context. diff --git a/include/linux/usb.h b/include/linux/usb.h index 65f78ca5d88e..73c7df489607 100644 --- a/include/linux/usb.h +++ b/include/linux/usb.h @@ -806,8 +806,10 @@ struct usbdrv_wrap { * @resume: Called when the device is being resumed by the system. * @reset_resume: Called when the suspended device has been reset instead * of being resumed. - * @pre_reset: Called by usb_reset_device() when the device - * is about to be reset. + * @pre_reset: Called by usb_reset_device() when the device is about to be + * reset. This routine must not return until the driver has no active + * URBs for the device, and no more URBs may be submitted until the + * post_reset method is called. * @post_reset: Called by usb_reset_device() after the device * has been reset * @id_table: USB drivers use ID table to support hotplugging. |