diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 909b32a4412f..0ed64eb68e48 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -2967,58 +2967,8 @@ static int prepare_ring(struct xhci_hcd *xhci, struct xhci_ring *ep_ring,
 	}
 
 	while (1) {
-		if (room_on_ring(xhci, ep_ring, num_trbs)) {
-			union xhci_trb *trb = ep_ring->enqueue;
-			unsigned int usable = ep_ring->enq_seg->trbs +
-					TRBS_PER_SEGMENT - 1 - trb;
-			u32 nop_cmd;
-
-			/*
-			 * Section 4.11.7.1 TD Fragments states that a link
-			 * TRB must only occur at the boundary between
-			 * data bursts (eg 512 bytes for 480M).
-			 * While it is possible to split a large fragment
-			 * we don't know the size yet.
-			 * Simplest solution is to fill the trb before the
-			 * LINK with nop commands.
-			 */
-			if (num_trbs == 1 || num_trbs <= usable || usable == 0)
-				break;
-
-			if (ep_ring->type != TYPE_BULK)
-				/*
-				 * While isoc transfers might have a buffer that
-				 * crosses a 64k boundary it is unlikely.
-				 * Since we can't add NOPs without generating
-				 * gaps in the traffic just hope it never
-				 * happens at the end of the ring.
-				 * This could be fixed by writing a LINK TRB
-				 * instead of the first NOP - however the
-				 * TRB_TYPE_LINK_LE32() calls would all need
-				 * changing to check the ring length.
-				 */
-				break;
-
-			if (num_trbs >= TRBS_PER_SEGMENT) {
-				xhci_err(xhci, "Too many fragments %d, max %d\n",
-						num_trbs, TRBS_PER_SEGMENT - 1);
-				return -EINVAL;
-			}
-
-			nop_cmd = cpu_to_le32(TRB_TYPE(TRB_TR_NOOP) |
-					ep_ring->cycle_state);
-			ep_ring->num_trbs_free -= usable;
-			do {
-				trb->generic.field[0] = 0;
-				trb->generic.field[1] = 0;
-				trb->generic.field[2] = 0;
-				trb->generic.field[3] = nop_cmd;
-				trb++;
-			} while (--usable);
-			ep_ring->enqueue = trb;
-			if (room_on_ring(xhci, ep_ring, num_trbs))
-				break;
-		}
+		if (room_on_ring(xhci, ep_ring, num_trbs))
+			break;
 
 		if (ep_ring == xhci->cmd_ring) {
 			xhci_err(xhci, "Do not support expand command ring\n");
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 3712359d18ba..6fe577d46fa2 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -4730,11 +4730,8 @@ int xhci_gen_setup(struct usb_hcd *hcd, xhci_get_quirks_t get_quirks)
 	struct device		*dev = hcd->self.controller;
 	int			retval;
 
-	/* Limit the block layer scatter-gather lists to half a segment. */
-	hcd->self.sg_tablesize = TRBS_PER_SEGMENT / 2;
-
-	/* support to build packet from discontinuous buffers */
-	hcd->self.no_sg_constraint = 1;
+	/* Accept arbitrarily long scatter-gather lists */
+	hcd->self.sg_tablesize = ~0;
 
 	/* XHCI controllers don't stop the ep queue on short packets :| */
 	hcd->self.no_stop_on_short = 1;
@@ -4760,6 +4757,14 @@ int xhci_gen_setup(struct usb_hcd *hcd, xhci_get_quirks_t get_quirks)
 		/* xHCI private pointer was set in xhci_pci_probe for the second
 		 * registered roothub.
 		 */
+		xhci = hcd_to_xhci(hcd);
+		/*
+		 * Support arbitrarily aligned sg-list entries on hosts without
+		 * TD fragment rules (which are currently unsupported).
+		 */
+		if (xhci->hci_version < 0x100)
+			hcd->self.no_sg_constraint = 1;
+
 		return 0;
 	}
 
@@ -4788,6 +4793,9 @@ int xhci_gen_setup(struct usb_hcd *hcd, xhci_get_quirks_t get_quirks)
 	if (xhci->hci_version > 0x96)
 		xhci->quirks |= XHCI_SPURIOUS_SUCCESS;
 
+	if (xhci->hci_version < 0x100)
+		hcd->self.no_sg_constraint = 1;
+
 	/* Make sure the HC is halted. */
 	retval = xhci_halt(xhci);
 	if (retval)
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index 9154fd6cf24c..58ed9d088e63 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1268,7 +1268,7 @@ union xhci_trb {
  * since the command ring is 64-byte aligned.
  * It must also be greater than 16.
  */
-#define TRBS_PER_SEGMENT	256
+#define TRBS_PER_SEGMENT	64
 /* Allow two commands + a link TRB, along with any reserved command TRBs */
 #define MAX_RSVD_CMD_TRBS	(TRBS_PER_SEGMENT - 3)
 #define TRB_SEGMENT_SIZE	(TRBS_PER_SEGMENT*16)
diff --git a/include/linux/usb.h b/include/linux/usb.h
index c716da18c668..7f6eb859873e 100644
--- a/include/linux/usb.h
+++ b/include/linux/usb.h
@@ -1265,8 +1265,6 @@ typedef void (*usb_complete_t)(struct urb *);
  * @sg: scatter gather buffer list, the buffer size of each element in
  * 	the list (except the last) must be divisible by the endpoint's
  * 	max packet size if no_sg_constraint isn't set in 'struct usb_bus'
- * 	(FIXME: scatter-gather under xHCI is broken for periodic transfers.
- * 	Do not use urb->sg for interrupt endpoints for now, only bulk.)
  * @num_mapped_sgs: (internal) number of mapped sg entries
  * @num_sgs: number of entries in the sg list
  * @transfer_buffer_length: How big is transfer_buffer.  The transfer may