r8169: honor jumbo settings when chipset is requested to start.

Some hardware start settings implicitely assume an usual 1500 bytes mtu
that can't be guaranteed because changes of mtu may be requested both
before and after the hardware is started.

Reported-by: Tomi Orava <tomimo@ncircle.nullnet.fi>
Signed-off-by: Francois Romieu <romieu@fr.zoreil.com>
Cc: Hayes Wang <hayeswang@realtek.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ethernet/realtek/r8169.c b/drivers/net/ethernet/realtek/r8169.c
index 8900398..28fb50a 100644
--- a/drivers/net/ethernet/realtek/r8169.c
+++ b/drivers/net/ethernet/realtek/r8169.c
@@ -4765,8 +4765,10 @@
 
 	RTL_W16(CPlusCmd, RTL_R16(CPlusCmd) & ~R8168_CPCMD_QUIRK_MASK);
 
-	rtl_tx_performance_tweak(pdev,
-		(0x5 << MAX_READ_REQUEST_SHIFT) | PCI_EXP_DEVCTL_NOSNOOP_EN);
+	if (tp->dev->mtu <= ETH_DATA_LEN) {
+		rtl_tx_performance_tweak(pdev, (0x5 << MAX_READ_REQUEST_SHIFT) |
+					 PCI_EXP_DEVCTL_NOSNOOP_EN);
+	}
 }
 
 static void rtl_hw_start_8168bef(struct rtl8169_private *tp)
@@ -4789,7 +4791,8 @@
 
 	RTL_W8(Config3, RTL_R8(Config3) & ~Beacon_en);
 
-	rtl_tx_performance_tweak(pdev, 0x5 << MAX_READ_REQUEST_SHIFT);
+	if (tp->dev->mtu <= ETH_DATA_LEN)
+		rtl_tx_performance_tweak(pdev, 0x5 << MAX_READ_REQUEST_SHIFT);
 
 	rtl_disable_clock_request(pdev);
 
@@ -4822,7 +4825,8 @@
 
 	RTL_W8(Config3, RTL_R8(Config3) & ~Beacon_en);
 
-	rtl_tx_performance_tweak(pdev, 0x5 << MAX_READ_REQUEST_SHIFT);
+	if (tp->dev->mtu <= ETH_DATA_LEN)
+		rtl_tx_performance_tweak(pdev, 0x5 << MAX_READ_REQUEST_SHIFT);
 
 	RTL_W16(CPlusCmd, RTL_R16(CPlusCmd) & ~R8168_CPCMD_QUIRK_MASK);
 }
@@ -4841,7 +4845,8 @@
 
 	RTL_W8(MaxTxPacketSize, TxPacketMax);
 
-	rtl_tx_performance_tweak(pdev, 0x5 << MAX_READ_REQUEST_SHIFT);
+	if (tp->dev->mtu <= ETH_DATA_LEN)
+		rtl_tx_performance_tweak(pdev, 0x5 << MAX_READ_REQUEST_SHIFT);
 
 	RTL_W16(CPlusCmd, RTL_R16(CPlusCmd) & ~R8168_CPCMD_QUIRK_MASK);
 }
@@ -4901,7 +4906,8 @@
 
 	RTL_W8(MaxTxPacketSize, TxPacketMax);
 
-	rtl_tx_performance_tweak(pdev, 0x5 << MAX_READ_REQUEST_SHIFT);
+	if (tp->dev->mtu <= ETH_DATA_LEN)
+		rtl_tx_performance_tweak(pdev, 0x5 << MAX_READ_REQUEST_SHIFT);
 
 	RTL_W16(CPlusCmd, RTL_R16(CPlusCmd) & ~R8168_CPCMD_QUIRK_MASK);
 }
@@ -4913,7 +4919,8 @@
 
 	rtl_csi_access_enable_1(tp);
 
-	rtl_tx_performance_tweak(pdev, 0x5 << MAX_READ_REQUEST_SHIFT);
+	if (tp->dev->mtu <= ETH_DATA_LEN)
+		rtl_tx_performance_tweak(pdev, 0x5 << MAX_READ_REQUEST_SHIFT);
 
 	RTL_W8(MaxTxPacketSize, TxPacketMax);
 
@@ -4972,7 +4979,8 @@
 
 	rtl_ephy_init(tp, e_info_8168e_1, ARRAY_SIZE(e_info_8168e_1));
 
-	rtl_tx_performance_tweak(pdev, 0x5 << MAX_READ_REQUEST_SHIFT);
+	if (tp->dev->mtu <= ETH_DATA_LEN)
+		rtl_tx_performance_tweak(pdev, 0x5 << MAX_READ_REQUEST_SHIFT);
 
 	RTL_W8(MaxTxPacketSize, TxPacketMax);
 
@@ -4998,7 +5006,8 @@
 
 	rtl_ephy_init(tp, e_info_8168e_2, ARRAY_SIZE(e_info_8168e_2));
 
-	rtl_tx_performance_tweak(pdev, 0x5 << MAX_READ_REQUEST_SHIFT);
+	if (tp->dev->mtu <= ETH_DATA_LEN)
+		rtl_tx_performance_tweak(pdev, 0x5 << MAX_READ_REQUEST_SHIFT);
 
 	rtl_eri_write(tp, 0xc0, ERIAR_MASK_0011, 0x0000, ERIAR_EXGMAC);
 	rtl_eri_write(tp, 0xb8, ERIAR_MASK_0011, 0x0000, ERIAR_EXGMAC);