[TG3]: Prevent dropped frames when flow-control is enabled.

drivers/net/tg3.c

@@ -4271,6 +4271,12 @@ static int tg3_reset_hw(struct tg3 *tp)
 	if (tp->pci_chip_rev_id == CHIPREV_ID_5703_A1)
 		tw32(MAC_SERDES_CFG, 0x616000);
 
+	/* Prevent chip from dropping frames when flow control
+	 * is enabled.
+	 */
+	tw32(MAC_LOW_WMARK_MAX_RX_FRAME, 2);
+	tr32(MAC_LOW_WMARK_MAX_RX_FRAME);
+
 	err = tg3_setup_phy(tp);
 	if (err)
 		return err;

drivers/net/tg3.h

@@ -456,6 +456,7 @@
 #define  RCV_RULE_DISABLE_MASK		 0x7fffffff
 #define MAC_RCV_RULE_CFG		0x00000500
 #define  RCV_RULE_CFG_DEFAULT_CLASS	0x00000008
+#define MAC_LOW_WMARK_MAX_RX_FRAME	0x00000504
 /* 0x504 --> 0x590 unused */
 #define MAC_SERDES_CFG			0x00000590
 #define MAC_SERDES_STAT			0x00000594