r8169:fix "rtl_counters_cond == 1 (loop: 1000, delay: 10)" log spam.

There will be a log spam when there is no cable plugged. Please refer to
following links. https://bugzilla.kernel.org/show_bug.cgi?id=104351
https://bugzilla.kernel.org/show_bug.cgi?id=107421

This issue is caused by runtime power management. When there is no cable
plugged, the driver will be suspend (runtime suspend) by OS and NIC will be
put into the D3 state. During this time, if OS call rtl8169_get_stats64()
to dump tally counter, because NIC is in D3 state, the register value read
by driver will return all 0xff. This will let driver think tally counter
flag is not toggled and then sends the warning message "rtl_counters_cond
== 1 (loop: 1000, delay: 10)" to kernel log.

For fixing this issue, 1.add checking driver's pm runtime status in
rtl8169_get_stats64(). 2.dump tally counter before going runtime suspend
for counter accuracy in runtime suspend.

Signed-off-by: Chunhao Lin <hau@realtek.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/realtek/r8169.c

@@ -7730,10 +7730,13 @@ rtl8169_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
 {
 	struct rtl8169_private *tp = netdev_priv(dev);
 	void __iomem *ioaddr = tp->mmio_addr;
+	struct pci_dev *pdev = tp->pci_dev;
 	struct rtl8169_counters *counters = tp->counters;
 	unsigned int start;
 
-	if (netif_running(dev))
+	pm_runtime_get_noresume(&pdev->dev);
+
+	if (netif_running(dev) && pm_runtime_active(&pdev->dev))
 		rtl8169_rx_missed(dev, ioaddr);
 
 	do {
@@ -7761,7 +7764,8 @@ rtl8169_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
 	 * Fetch additonal counter values missing in stats collected by driver
 	 * from tally counters.
 	 */
-	rtl8169_update_counters(dev);
+	if (pm_runtime_active(&pdev->dev))
+		rtl8169_update_counters(dev);
 
 	/*
 	 * Subtract values fetched during initalization.
@@ -7774,6 +7778,8 @@ rtl8169_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
 	stats->tx_aborted_errors = le16_to_cpu(counters->tx_aborted) -
 		le16_to_cpu(tp->tc_offset.tx_aborted);
 
+	pm_runtime_put_noidle(&pdev->dev);
+
 	return stats;
 }
 
@@ -7853,6 +7859,10 @@ static int rtl8169_runtime_suspend(struct device *device)
 
 	rtl8169_net_suspend(dev);
 
+	/* Update counters before going runtime suspend */
+	rtl8169_rx_missed(dev, tp->mmio_addr);
+	rtl8169_update_counters(dev);
+
 	return 0;
 }