[Intel-wired-lan] [PATCH] e1000e: i219 execute unit hang fix on every reset or power state transition

[Yanir Lubetkin]

after testing various cases, the conclusion is that the fix MUST be executed BEFORE
any event that the HW is reset or transition to D3. to fix that I moved the execution
to the relevant places but per Alexander Duyck's review, ensure now that the DMA is
valid and was not freed before manipulating the ring.

Signed-off-by: Yanir Lubetkin <yanirx.lubetkin at intel.com>
---
 drivers/net/ethernet/intel/e1000e/netdev.c | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c
index 76b1a90..3f561f3 100644
--- a/drivers/net/ethernet/intel/e1000e/netdev.c
+++ b/drivers/net/ethernet/intel/e1000e/netdev.c
@@ -4043,6 +4043,8 @@ void e1000e_reset(struct e1000_adapter *adapter)
 		}
 	}
 
+	if (hw->mac.type == e1000_pch_spt)
+		e1000_flush_desc_rings(adapter);
 	/* Allow time for pending master requests to run */
 	mac->ops.reset_hw(hw);
 
@@ -4215,10 +4217,6 @@ void e1000e_down(struct e1000_adapter *adapter, bool reset)
 	spin_unlock(&adapter->stats64_lock);
 
 	e1000e_flush_descriptors(adapter);
-	if (hw->mac.type == e1000_pch_spt)
-		e1000_flush_desc_rings(adapter);
-	e1000_clean_tx_ring(adapter->tx_ring);
-	e1000_clean_rx_ring(adapter->rx_ring);
 
 	adapter->link_speed = 0;
 	adapter->link_duplex = 0;
@@ -4229,8 +4227,14 @@ void e1000e_down(struct e1000_adapter *adapter, bool reset)
 	    e1000_lv_jumbo_workaround_ich8lan(hw, false))
 		e_dbg("failed to disable jumbo frame workaround mode\n");
 
-	if (reset && !pci_channel_offline(adapter->pdev))
-		e1000e_reset(adapter);
+        if (!pci_channel_offline(adapter->pdev)) {
+                if(reset)
+                        e1000e_reset(adapter);
+                else if (hw->mac.type == e1000_pch_spt)
+                        e1000_flush_desc_rings(adapter);
+        }
+	e1000_clean_tx_ring(adapter->tx_ring);
+	e1000_clean_rx_ring(adapter->rx_ring);
 }
 
 void e1000e_reinit_locked(struct e1000_adapter *adapter)
-- 
2.1.0

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