From: Greg KH <gre...@linuxfoundation.org>
3.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Tushar Dave <tushar.n.d...@intel.com>
commit d0efa8f23a644f7cb7d1f8e78dd9a223efa412a3 upstream.
SYNCH bit and IV bit of RXCW register are sticky. Before examining these bits,
RXCW should be read twice to filter out one-time false events and have correct
values for these bits. Incorrect values of these bits in link check logic can
cause weird link stability issues if auto-negotiation fails.
Reported-by: Dean Nelson <dnel...@redhat.com>
Signed-off-by: Tushar Dave <tushar.n.d...@intel.com>
Reviewed-by: Bruce Allan <bruce.w.al...@intel.com>
Tested-by: Jeff Pieper <jeffrey.e.pie...@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirs...@intel.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
drivers/net/ethernet/intel/e1000e/82571.c | 3 +++
1 file changed, 3 insertions(+)
--- a/drivers/net/ethernet/intel/e1000e/82571.c
+++ b/drivers/net/ethernet/intel/e1000e/82571.c
@@ -1553,6 +1553,9 @@ static s32 e1000_check_for_serdes_link_8
ctrl = er32(CTRL);
status = er32(STATUS);
rxcw = er32(RXCW);
+ /* SYNCH bit and IV bit are sticky */
+ udelay(10);
+ rxcw = er32(RXCW);
if ((rxcw & E1000_RXCW_SYNCH) && !(rxcw & E1000_RXCW_IV)) {
--
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