e1000e: Correct link check logic for 82571 serdes

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.

CC: stable <stable@vger.kernel.org> [2.6.38+]
Reported-by: Dean Nelson <dnelson@redhat.com>
Signed-off-by: Tushar Dave <tushar.n.dave@intel.com>
Reviewed-by: Bruce Allan <bruce.w.allan@intel.com>
Tested-by: Jeff Pieper <jeffrey.e.pieper@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
This commit is contained in:
Tushar Dave 2012-07-12 08:56:56 +00:00 коммит произвёл Jeff Kirsher
Родитель 7ac2908e4b
Коммит d0efa8f23a
1 изменённых файлов: 3 добавлений и 0 удалений

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@ -1572,6 +1572,9 @@ 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)) {