USB: xhci: Limit bus sg_tablesize to 62 TRBs.

commit bc88d2eba5 upstream.

When a scatter-gather list is enqueued to the xHCI driver, it translates
each entry into a transfer request block (TRB).  Only 63 TRBs can be
used per ring segment, and there must be one additional TRB reserved to
make sure the hardware does not think the ring is empty (so the enqueue
pointer doesn't equal the dequeue pointer).  Limit the bus sg_tablesize
to 62 TRBs.

Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Sarah Sharp
2010-05-18 16:05:21 -07:00
committed by Greg Kroah-Hartman
parent 863bbb5107
commit 98edccb42c

View File

@@ -54,7 +54,7 @@ static int xhci_pci_setup(struct usb_hcd *hcd)
struct pci_dev *pdev = to_pci_dev(hcd->self.controller);
int retval;
hcd->self.sg_tablesize = TRBS_PER_SEGMENT - 1;
hcd->self.sg_tablesize = TRBS_PER_SEGMENT - 2;
xhci->cap_regs = hcd->regs;
xhci->op_regs = hcd->regs +