[PATCH net-next 2/2] r8169: don't activate ASPM in chip if OS can't control ASPM

[Heiner Kallweit <hkallweit1@gmail.com>]

Certain chip version / board combinations have massive problems if
ASPM is active. If BIOS enables ASPM and doesn't let OS control it,
then we may have a problem with the current code. Therefore check the
return code of pci_disable_link_state() and don't enable ASPM in the
network chip if OS can't control ASPM.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
---
 drivers/net/ethernet/realtek/r8169_main.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/realtek/r8169_main.c b/drivers/net/ethernet/realtek/r8169_main.c
index 2e2a74aa0..48b8a90f7 100644
--- a/drivers/net/ethernet/realtek/r8169_main.c
+++ b/drivers/net/ethernet/realtek/r8169_main.c
@@ -652,6 +652,7 @@ struct rtl8169_private {
 
 	unsigned irq_enabled:1;
 	unsigned supports_gmii:1;
+	unsigned aspm_manageable:1;
 	dma_addr_t counters_phys_addr;
 	struct rtl8169_counters *counters;
 	struct rtl8169_tc_offsets tc_offset;
@@ -4286,7 +4287,8 @@ static void rtl_pcie_state_l2l3_disable(struct rtl8169_private *tp)
 
 static void rtl_hw_aspm_clkreq_enable(struct rtl8169_private *tp, bool enable)
 {
-	if (enable) {
+	/* Don't enable ASPM in the chip if OS can't control ASPM */
+	if (enable && tp->aspm_manageable) {
 		RTL_W8(tp, Config5, RTL_R8(tp, Config5) | ASPM_en);
 		RTL_W8(tp, Config2, RTL_R8(tp, Config2) | ClkReqEn);
 	} else {
@@ -6678,7 +6680,9 @@ static int rtl_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 	/* Disable ASPM completely as that cause random device stop working
 	 * problems as well as full system hangs for some PCIe devices users.
 	 */
-	pci_disable_link_state(pdev, PCIE_LINK_STATE_L0S | PCIE_LINK_STATE_L1);
+	rc = pci_disable_link_state(pdev, PCIE_LINK_STATE_L0S |
+					  PCIE_LINK_STATE_L1);
+	tp->aspm_manageable = !rc;
 
 	/* enable device (incl. PCI PM wakeup and hotplug setup) */
 	rc = pcim_enable_device(pdev);
-- 
2.22.0