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USB: Add support for SuperSpeed isoc endpoints

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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: Paul Zimmerman <paulz@synopsys.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: stable@kernel.org
This commit is contained in:
Paul Zimmerman 2011-02-28 18:11:27 -08:00 committed by Sarah Sharp
parent ba0a4d9aaa
commit 500132a0f2
2 changed files with 12 additions and 1 deletions
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11
drivers/usb/core/urb.c
View file

@ -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);

2
include/linux/usb/ch9.h
View file

@ -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))
/*-------------------------------------------------------------------------*/