[PATCH net-next v2] r8169: reset bus if NIC isn't accessible after tx timeout

[Heiner Kallweit <hkallweit1@gmail.com>]

ASPM issues may result in the NIC not being accessible any longer.
In this case disabling ASPM may not work. Therefore detect this case
by checking whether register reads return ~0, and try to make the
NIC accessible again by resetting the secondary bus.

v2:
- add exception handling for the case that pci_reset_bus() fails

Suggested-by: Alexander Duyck <alexander.duyck@gmail.com>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
---
 drivers/net/ethernet/realtek/r8169_main.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/net/ethernet/realtek/r8169_main.c b/drivers/net/ethernet/realtek/r8169_main.c
index 49c124d8e..02ef98a95 100644
--- a/drivers/net/ethernet/realtek/r8169_main.c
+++ b/drivers/net/ethernet/realtek/r8169_main.c
@@ -4535,6 +4535,16 @@ static void rtl_task(struct work_struct *work)
 		goto out_unlock;
 
 	if (test_and_clear_bit(RTL_FLAG_TASK_TX_TIMEOUT, tp->wk.flags)) {
+		/* if chip isn't accessible, reset bus to revive it */
+		if (RTL_R32(tp, TxConfig) == ~0) {
+			ret = pci_reset_bus(tp->pci_dev);
+			if (ret < 0) {
+				netdev_err(tp->dev, "Can't reset secondary PCI bus, detach NIC\n");
+				netif_device_detach(tp->dev);
+				goto out_unlock;
+			}
+		}
+
 		/* ASPM compatibility issues are a typical reason for tx timeouts */
 		ret = pci_disable_link_state(tp->pci_dev, PCIE_LINK_STATE_L1 |
 							  PCIE_LINK_STATE_L0S);
-- 
2.39.0