From df4372866de83261b79bf7af24c058649ed0f2eb Mon Sep 17 00:00:00 2001 From: Tushar Dave Date: Thu, 12 Jul 2012 08:56:56 +0000 Subject: [PATCH] e1000e: Correct link check logic for 82571 serdes 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 Signed-off-by: Tushar Dave Reviewed-by: Bruce Allan Tested-by: Jeff Pieper Signed-off-by: Jeff Kirsher Signed-off-by: Ben Hutchings --- drivers/net/ethernet/intel/e1000e/82571.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/net/ethernet/intel/e1000e/82571.c b/drivers/net/ethernet/intel/e1000e/82571.c index e556fc3a3cf6..3072d35cc4b3 100644 --- a/drivers/net/ethernet/intel/e1000e/82571.c +++ b/drivers/net/ethernet/intel/e1000e/82571.c @@ -1571,6 +1571,9 @@ static s32 e1000_check_for_serdes_link_82571(struct e1000_hw *hw) 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)) { -- 2.39.5