Commit 158886cd authored Nov 30, 2011 by Andiry Xu Committed by Sarah Sharp Dec 01, 2011

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 <andiry.xu@amd.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Reported-by: Oliver Neukum <oneukum@suse.de>

parent 6414e94c

drivers/usb/host/xhci.c

+4 −1

Original line number	Diff line number	Diff line
		@@ -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);

Admin message