From: Andiry Xu Date: Wed, 30 Nov 2011 08:37:41 +0000 (+0800) Subject: xHCI: fix bug in xhci_clear_command_ring() X-Git-Tag: v3.2-rc5~50^2^2~1 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=158886cd2cf4599e04f9b7e10cb767f5f39b14f1;p=profile%2Fcommon%2Fkernel-common.git xHCI: fix bug in xhci_clear_command_ring() When system enters suspend, xHCI driver clears command ring by writing zero to all the TRBs. However, this also writes zero to the Link TRB, and the ring is mangled. This may cause driver accesses wrong memory address and the result is unpredicted. When clear the command ring, keep the last Link TRB intact, only clear its cycle bit. This should fix the "command ring full" issue reported by Oliver Neukum. This should be backported to stable kernels as old as 2.6.37, since the commit 89821320 "xhci: Fix command ring replay after resume" is merged. Signed-off-by: Andiry Xu Signed-off-by: Sarah Sharp Reported-by: Oliver Neukum --- diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c index aa94c01..a1afb7c 100644 --- a/drivers/usb/host/xhci.c +++ b/drivers/usb/host/xhci.c @@ -711,7 +711,10 @@ static void xhci_clear_command_ring(struct xhci_hcd *xhci) ring = xhci->cmd_ring; seg = ring->deq_seg; do { - memset(seg->trbs, 0, SEGMENT_SIZE); + memset(seg->trbs, 0, + sizeof(union xhci_trb) * (TRBS_PER_SEGMENT - 1)); + seg->trbs[TRBS_PER_SEGMENT - 1].link.control &= + cpu_to_le32(~TRB_CYCLE); seg = seg->next; } while (seg != ring->deq_seg);