Revert "xhci: Set scatter-gather limit to avoid failed block writes."

This reverts commit f2d9b991c549f159dc9ae81f77d8206c790cbfee.

We are ripping out commit 35773dac5f862cb1c82ea151eba3e2f6de51ec3e "usb:
xhci: Link TRB must not occur within a USB payload burst" because it's a
hack that caused regressions in the usb-storage and userspace USB
drivers that use usbfs and libusb.  This commit attempted to fix the
issues with that patch.

Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: stable@vger.kernel.org #3.12

2 files changed, 3 insertions, 3 deletions

diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 86a2e834fdff..6fe577d46fa2 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -4730,8 +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;
+        /* 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;
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)