diff options
Diffstat (limited to 'include/linux/usb')
| -rw-r--r-- | include/linux/usb/gadget.h | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h index 0ebedaec075..0460a746480 100644 --- a/include/linux/usb/gadget.h +++ b/include/linux/usb/gadget.h @@ -33,7 +33,8 @@ struct usb_ep; * @short_not_ok: When reading data, makes short packets be * treated as errors (queue stops advancing till cleanup). * @complete: Function called when request completes, so this request and - * its buffer may be re-used. + * its buffer may be re-used. The function will always be called with + * interrupts disabled, and it must not sleep. * Reads terminate with a short packet, or when the buffer fills, * whichever comes first. When writes terminate, some data bytes * will usually still be in flight (often in a hardware fifo). @@ -271,7 +272,10 @@ static inline void usb_ep_free_request(struct usb_ep *ep, * (Note that some USB device controllers disallow protocol stall responses * in some cases.) When control responses are deferred (the response is * written after the setup callback returns), then usb_ep_set_halt() may be - * used on ep0 to trigger protocol stalls. + * used on ep0 to trigger protocol stalls. Depending on the controller, + * it may not be possible to trigger a status-stage protocol stall when the + * data stage is over, that is, from within the response's completion + * routine. * * For periodic endpoints, like interrupt or isochronous ones, the usb host * arranges to poll once per interval, and the gadget driver usually will |