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Commit 500132a0 authored by Paul Zimmerman's avatar Paul Zimmerman Committed by Sarah Sharp
Browse files

USB: Add support for SuperSpeed isoc endpoints 



Use the Mult and bMaxBurst values from the endpoint companion
descriptor to calculate the max length of an isoc transfer.

Add USB_SS_MULT macro to access Mult field of bmAttributes, at
Sarah's suggestion.

This patch should be queued for the 2.6.36 and 2.6.37 stable trees, since
those were the first kernels to have isochronous support for SuperSpeed
devices.

Signed-off-by: default avatarPaul Zimmerman <paulz@synopsys.com>
Signed-off-by: default avatarSarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: stable@kernel.org
parent ba0a4d9a

drivers/usb/core/urb.c

+10 −1
Original line number Diff line number Diff line
@@ -366,7 +366,16 @@ int usb_submit_urb(struct urb *urb, gfp_t mem_flags) 
	if (xfertype == USB_ENDPOINT_XFER_ISOC) {

		int	n, len;



		/* FIXME SuperSpeed isoc endpoints have up to 16 bursts */

		/* SuperSpeed isoc endpoints have up to 16 bursts of up to

		 * 3 packets each

		 */

		if (dev->speed == USB_SPEED_SUPER) {

			int     burst = 1 + ep->ss_ep_comp.bMaxBurst;

			int     mult = USB_SS_MULT(ep->ss_ep_comp.bmAttributes);

			max *= burst;

			max *= mult;

		}



		/* "high bandwidth" mode, 1-3 packets/uframe? */

		if (dev->speed == USB_SPEED_HIGH) {

			int	mult = 1 + ((max >> 11) & 0x03);

include/linux/usb/ch9.h

+2 −0
Original line number Diff line number Diff line
@@ -585,6 +585,8 @@ struct usb_ss_ep_comp_descriptor { 
#define USB_DT_SS_EP_COMP_SIZE		6

/* Bits 4:0 of bmAttributes if this is a bulk endpoint */

#define USB_SS_MAX_STREAMS(p)		(1 << ((p) & 0x1f))

/* Bits 1:0 of bmAttributes if this is an isoc endpoint */

#define USB_SS_MULT(p)			(1 + ((p) & 0x3))



/*-------------------------------------------------------------------------*/