diff options
Diffstat (limited to 'include/linux/usb.h')
| -rw-r--r-- | include/linux/usb.h | 18 |
1 files changed, 13 insertions, 5 deletions
diff --git a/include/linux/usb.h b/include/linux/usb.h index 8c9f053111b..ce1323c4e47 100644 --- a/include/linux/usb.h +++ b/include/linux/usb.h @@ -1055,7 +1055,8 @@ typedef void (*usb_complete_t)(struct urb *); * @number_of_packets: Lists the number of ISO transfer buffers. * @interval: Specifies the polling interval for interrupt or isochronous * transfers. The units are frames (milliseconds) for full and low - * speed devices, and microframes (1/8 millisecond) for highspeed ones. + * speed devices, and microframes (1/8 millisecond) for highspeed + * and SuperSpeed devices. * @error_count: Returns the number of ISO transfers that reported errors. * @context: For use in completion functions. This normally points to * request-specific driver context. @@ -1286,9 +1287,16 @@ static inline void usb_fill_bulk_urb(struct urb *urb, * * Initializes a interrupt urb with the proper information needed to submit * it to a device. - * Note that high speed interrupt endpoints use a logarithmic encoding of - * the endpoint interval, and express polling intervals in microframes - * (eight per millisecond) rather than in frames (one per millisecond). + * + * Note that High Speed and SuperSpeed interrupt endpoints use a logarithmic + * encoding of the endpoint interval, and express polling intervals in + * microframes (eight per millisecond) rather than in frames (one per + * millisecond). + * + * Wireless USB also uses the logarithmic encoding, but specifies it in units of + * 128us instead of 125us. For Wireless USB devices, the interval is passed + * through to the host controller, rather than being translated into microframe + * units. */ static inline void usb_fill_int_urb(struct urb *urb, struct usb_device *dev, @@ -1305,7 +1313,7 @@ static inline void usb_fill_int_urb(struct urb *urb, urb->transfer_buffer_length = buffer_length; urb->complete = complete_fn; urb->context = context; - if (dev->speed == USB_SPEED_HIGH) + if (dev->speed == USB_SPEED_HIGH || dev->speed == USB_SPEED_SUPER) urb->interval = 1 << (interval - 1); else urb->interval = interval; |