lan743x: Fix TX Stall Issue

BryanW11731-MCHP · davem330 · commit deb6bfabdbb6 · 2019-03-13T13:41:46.000-07:00
It has been observed that tx queue may stall while downloading from certain web sites (example www.speedtest.net) The cause has been tracked down to a corner case where the tx interrupt vector was disabled automatically, but was not re enabled later. The lan743x has two mechanisms to enable/disable individual interrupts. Interrupts can be enabled/disabled by individual source, and they can also be enabled/disabled by individual vector which has been mapped to the source. Both must be enabled for interrupts to work properly. The TX code path, primarily uses the interrupt enable/disable of the TX source bit, while leaving the vector enabled all the time. However, while investigating this issue it was noticed that the driver requested the use of the vector auto clear feature. The test above revealed a case where the vector enable was cleared unintentionally. This patch fixes the issue by deleting the lines that request the vector auto clear feature to be used. Fixes: 23f0703 ("lan743x: Add main source files for new lan743x driver") Signed-off-by: Bryan Whitehead <Bryan.Whitehead@microchip.com> Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ethernet/microchip/lan743x_main.c b/drivers/net/ethernet/microchip/lan743x_main.c
@@ -585,8 +585,7 @@ static int lan743x_intr_open(struct lan743x_adapter *adapter)
 
 		if (adapter->csr.flags &
 		   LAN743X_CSR_FLAG_SUPPORTS_INTR_AUTO_SET_CLR) {
-			flags = LAN743X_VECTOR_FLAG_VECTOR_ENABLE_AUTO_CLEAR |
-				LAN743X_VECTOR_FLAG_VECTOR_ENABLE_AUTO_SET |
+			flags = LAN743X_VECTOR_FLAG_VECTOR_ENABLE_AUTO_SET |
 				LAN743X_VECTOR_FLAG_SOURCE_ENABLE_AUTO_SET |
 				LAN743X_VECTOR_FLAG_SOURCE_ENABLE_AUTO_CLEAR |
 				LAN743X_VECTOR_FLAG_SOURCE_STATUS_AUTO_CLEAR;
@@ -599,12 +598,6 @@ static int lan743x_intr_open(struct lan743x_adapter *adapter)
 			/* map TX interrupt to vector */
 			int_vec_map1 |= INT_VEC_MAP1_TX_VEC_(index, vector);
 			lan743x_csr_write(adapter, INT_VEC_MAP1, int_vec_map1);
-			if (flags &
-			    LAN743X_VECTOR_FLAG_VECTOR_ENABLE_AUTO_CLEAR) {
-				int_vec_en_auto_clr |= INT_VEC_EN_(vector);
-				lan743x_csr_write(adapter, INT_VEC_EN_AUTO_CLR,
-						  int_vec_en_auto_clr);
-			}
 
 			/* Remove TX interrupt from shared mask */
 			intr->vector_list[0].int_mask &= ~int_bit;
