[PATCH net v2] 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 <redacted>
---
 drivers/net/ethernet/realtek/r8169.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/realtek/r8169.c b/drivers/net/ethernet/realtek/r8169.c
index 537974c..a645f8d 100644
--- a/drivers/net/ethernet/realtek/r8169.c
+++ b/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;
 }
 

@@ -7842,6 +7848,12 @@ static int rtl8169_runtime_suspend(struct device *device)
 	struct pci_dev *pdev = to_pci_dev(device);
 	struct net_device *dev = pci_get_drvdata(pdev);
 	struct rtl8169_private *tp = netdev_priv(dev);
+	void __iomem *ioaddr = tp->mmio_addr;
+
+	/* Update counters before going runtime suspend */
+	if (netif_running(dev))
+		rtl8169_rx_missed(dev, ioaddr);
+	rtl8169_update_counters(dev);
 
 	if (!tp->TxDescArray)
 		return 0;

-- 
1.9.1

Chunhao Lin [off-list ref] :
[...]

+ 	struct device *d = &tp->pci_dev->dev;

(the patch does not use pdev alone)

[...]

pm_runtime_active() won't change after pm_runtime_get_noresume(). You may
set a boolean active = pm_runtime_active(d) before testing netif_running().

[...]

Nits:

- the tp->TxDescArray test provides the required synchronization: see
  rtl8169_{open/close} and their pm_runtime_{get / put}.

- ioaddr is not really needed : tp->mmio_addr appears only once and it does
  not mess the 72..80 cols limit.

- even if the device can only be automatically runtime suspended some time
  after a link down event, you may address davem's point regarding stats
  reliability and move rtl8169_rx_missed + rtl8169_update_counters after
  rtl8169_net_suspend.

-- 
Ueimor

Nits:

- the tp->TxDescArray test provides the required synchronization: see
  rtl8169_{open/close} and their pm_runtime_{get / put}.

- ioaddr is not really needed : tp->mmio_addr appears only once and it does
  not mess the 72..80 cols limit.

- even if the device can only be automatically runtime suspended some time
  after a link down event, you may address davem's point regarding stats
  reliability and move rtl8169_rx_missed + rtl8169_update_counters after
  rtl8169_net_suspend.

I will submit the new patch according to your advice.

Thanks.

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