[PATCH 3.12 59/82] Revert "xhci: Set scatter-gather limit to avoid failed block writes."

Greg Kroah-Hartman
2014-02-21T00:29:48Z

From: Sarah Sharp <sarah.a.sharp@linux.intel.com>

commit 1386ff75797a187df324062fb4e929152392da88 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/usb/host/xhci.c | 4 ++--
drivers/usb/host/xhci.h | 2 +-
2 files changed, 3 insertions(+), 3 deletions(-)

--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -4727,8 +4727,8 @@ int xhci_gen_setup(struct usb_hcd *hcd,
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;
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1262,7 +1262,7 @@ 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)