From: Matt Turner <matt.turner@intel.com>
Date: Tue, 7 Nov 2017 14:13:30 -0800
Subject: e1000e: Set HTHRESH when PTHRESH is used
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Patch-mainline: v4.16-rc1
Git-commit: b701cacdbcfb65a5ba38d9d4121c12a0a4eaa01a
References: bsc#1056664 FATE#322185

According to section 12.0.3.4.13 "Receive Descriptor Control - RXDCTL"
of the Intel® 82579 Gigabit Ethernet PHY Datasheet v2.1:

    "HTHRESH should be given a non zero value when ever PTHRESH is
     used."

In RXDCTL(0), PTHRESH lives at bits 5:0, and HTHREST lives at bits 13:8.
Set only bit 8 of HTHREST as is done in e1000_flush_rx_ring(). Found by
inspection.

Signed-off-by: Matt Turner <matt.turner@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Acked-by: Benjamin Poirier <bpoirier@suse.com>
---
 drivers/net/ethernet/intel/e1000e/netdev.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/net/ethernet/intel/e1000e/netdev.c
+++ b/drivers/net/ethernet/intel/e1000e/netdev.c
@@ -3303,7 +3303,7 @@ static void e1000_configure_rx(struct e1
 		if (adapter->flags & FLAG_IS_ICH) {
 			u32 rxdctl = er32(RXDCTL(0));
 
-			ew32(RXDCTL(0), rxdctl | 0x3);
+			ew32(RXDCTL(0), rxdctl | 0x3 | BIT(8));
 		}
 
 		pm_qos_update_request(&adapter->pm_qos_req, lat);