From d478eb44f7a6b53256ae399fa7e597525b4034ee Mon Sep 17 00:00:00 2001 From: Bruce Allan Date: Tue, 16 Nov 2010 19:50:13 -0800 Subject: [PATCH] e1000e: 82571 SerDes link handle null code word from partner SerDes Link detection on certain 82571 mezzanine cards can fail when the link is forced, the link partner does not recognize forced link and the link partner sends null code words. Detect the null code words and return to auto-negotiation state which causes the link partner to begin responding with valid code words. Within a reasonable interval the link will finally settle as forced by both partners. Signed-off-by: Bruce Allan Signed-off-by: Jeff Kirsher --- drivers/net/e1000e/82571.c | 4 +++- drivers/net/e1000e/defines.h | 1 + 2 files changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/net/e1000e/82571.c b/drivers/net/e1000e/82571.c index 7236f1a53ba0..235856375ff3 100644 --- a/drivers/net/e1000e/82571.c +++ b/drivers/net/e1000e/82571.c @@ -1431,8 +1431,10 @@ static s32 e1000_check_for_serdes_link_82571(struct e1000_hw *hw) * auto-negotiation in the TXCW register and disable * forced link in the Device Control register in an * attempt to auto-negotiate with our link partner. + * If the partner code word is null, stop forcing + * and restart auto negotiation. */ - if (rxcw & E1000_RXCW_C) { + if ((rxcw & E1000_RXCW_C) || !(rxcw & E1000_RXCW_CW)) { /* Enable autoneg, and unforce link up */ ew32(TXCW, mac->txcw); ew32(CTRL, (ctrl & ~E1000_CTRL_SLU)); diff --git a/drivers/net/e1000e/defines.h b/drivers/net/e1000e/defines.h index d3f7a9c3f973..016ea383145a 100644 --- a/drivers/net/e1000e/defines.h +++ b/drivers/net/e1000e/defines.h @@ -516,6 +516,7 @@ #define E1000_TXCW_ANE 0x80000000 /* Auto-neg enable */ /* Receive Configuration Word */ +#define E1000_RXCW_CW 0x0000ffff /* RxConfigWord mask */ #define E1000_RXCW_IV 0x08000000 /* Receive config invalid */ #define E1000_RXCW_C 0x20000000 /* Receive config */ #define E1000_RXCW_SYNCH 0x40000000 /* Receive config synch */ -- 2.39.2