Use the Mult and bMaxBurst values from the endpoint companion
descriptor to calculate the max length of an isoc transfer.
v2 - Add USB_SS_MULT macro to access Mult field of bmAttributes, at
Sarah's suggestion.
Signed-off-by: Paul Zimmerman <paulz@xxxxxxxxxxxx>
---
drivers/usb/core/urb.c | 11 ++++++++++-
include/linux/usb/ch9.h | 2 ++
2 files changed, 12 insertions(+), 1 deletions(-)
diff --git a/drivers/usb/core/urb.c b/drivers/usb/core/urb.c
index c14fc08..ae334b0 100644
--- a/drivers/usb/core/urb.c
+++ b/drivers/usb/core/urb.c
@@ -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);
diff --git a/include/linux/usb/ch9.h b/include/linux/usb/ch9.h
index 34316ba..b72f305 100644
--- a/include/linux/usb/ch9.h
+++ b/include/linux/usb/ch9.h
@@ -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))
/*-------------------------------------------------------------------------*/
--
1.6.5.1.69.g36942
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