diff options
| author | Bruce Allan <bruce.w.allan@intel.com> | 2013-03-06 13:02:36 +0400 |
|---|---|---|
| committer | Jeff Kirsher <jeffrey.t.kirsher@intel.com> | 2013-03-28 10:25:36 +0400 |
| commit | 772d05c51c4f4896c120ad418b1e91144a2ac813 (patch) | |
| tree | 0c67bd6877d7c121030d34d1de86832c807d2d53 /drivers/net/ethernet/intel/e1000e/ich8lan.c | |
| parent | bb034512da74dce901f738f7c7cea332ff971608 (diff) | |
| download | linux-772d05c51c4f4896c120ad418b1e91144a2ac813.tar.xz | |
e1000e: slow performance between two 82579 connected via 10Mbit hub
Two 82579 LOMs connected via a 10Mb hub experience extraordinarily low
performance. This is because 82579 is excessively aggressive on transmit
at 10Mb half-duplex and will not provide sufficient time for the link
partner to transmit. When the link partner is also 82579, the result is a
lot of collisions (and corresponding re-transmits) that cause the poor
performance. To work-around this issue, significantly increase the IPG in
the MAC to allow enough gap for the link partner to transmit and reduce the
Rx latency in the analog PHY to 0 to reduce the number of collisions.
Signed-off-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>
Diffstat (limited to 'drivers/net/ethernet/intel/e1000e/ich8lan.c')
| -rw-r--r-- | drivers/net/ethernet/intel/e1000e/ich8lan.c | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/drivers/net/ethernet/intel/e1000e/ich8lan.c b/drivers/net/ethernet/intel/e1000e/ich8lan.c index 1cdec5fd2129..4f2f0f69a48e 100644 --- a/drivers/net/ethernet/intel/e1000e/ich8lan.c +++ b/drivers/net/ethernet/intel/e1000e/ich8lan.c @@ -871,6 +871,34 @@ static s32 e1000_check_for_copper_link_ich8lan(struct e1000_hw *hw) return ret_val; } + /* When connected at 10Mbps half-duplex, 82579 parts are excessively + * aggressive resulting in many collisions. To avoid this, increase + * the IPG and reduce Rx latency in the PHY. + */ + if ((hw->mac.type == e1000_pch2lan) && link) { + u32 reg; + reg = er32(STATUS); + if (!(reg & (E1000_STATUS_FD | E1000_STATUS_SPEED_MASK))) { + reg = er32(TIPG); + reg &= ~E1000_TIPG_IPGT_MASK; + reg |= 0xFF; + ew32(TIPG, reg); + + /* Reduce Rx latency in analog PHY */ + ret_val = hw->phy.ops.acquire(hw); + if (ret_val) + return ret_val; + + ret_val = + e1000_write_emi_reg_locked(hw, I82579_RX_CONFIG, 0); + + hw->phy.ops.release(hw); + + if (ret_val) + return ret_val; + } + } + /* Work-around I218 hang issue */ if ((hw->adapter->pdev->device == E1000_DEV_ID_PCH_LPTLP_I218_LM) || (hw->adapter->pdev->device == E1000_DEV_ID_PCH_LPTLP_I218_V)) { |