r8169: 8168b Tx performance tweak

Signed-off-by: NFrancois Romieu <romieu@fr.zoreil.com>
Cc: Edward Hsu <edward_hsu@realtek.com.tw>

drivers/net/r8169.c

@@ -2386,7 +2386,8 @@ static void rtl_ephy_init(void __iomem *ioaddr, struct ephy_info *e, int len)
 
 static void rtl_hw_start_8168bb(void __iomem *ioaddr, struct pci_dev *pdev)
 {
-	rtl_tx_performance_tweak(pdev, 0x5 << MAX_READ_REQUEST_SHIFT);
+	rtl_tx_performance_tweak(pdev,
+		(0x5 << MAX_READ_REQUEST_SHIFT) | PCI_EXP_DEVCTL_NOSNOOP_EN);
 }
 
 static void rtl_hw_start_8168bef(void __iomem *ioaddr, struct pci_dev *pdev)