[PATCH v3] rtlwifi: rtl8723be: Disable ASPM if RTL8723BE connects to Intel PCI bridge

[Jian-Hong Pan <jhp@endlessos.org>]

Disable RTL8723BE's ASPM in a PCI quirk and rtl8723be module if the
Realtek RTL8723BE PCIe Wireless adapter connects to some Intel PCI
bridges, such as Skylake and Kabylake. Otherwise, the PCI AER flood
hangs system:

pcieport 0000:00:1c.5: PCIe Bus Error: severity=Corrected, type=Physical Layer, (Receiver ID)
pcieport 0000:00:1c.5:   device [8086:9d15] error status/mask=00000001/00002000
pcieport 0000:00:1c.5:    [ 0] RxErr                  (First)
pcieport 0000:00:1c.5: AER: Corrected error received: 0000:00:1c.5
pcieport 0000:00:1c.5: AER: can't find device of ID00e5
pcieport 0000:00:1c.5: AER: Corrected error received: 0000:00:1c.5
pcieport 0000:00:1c.5: AER: can't find device of ID00e5
pcieport 0000:00:1c.5: AER: Multiple Corrected error received: 0000:00:1c.5
pcieport 0000:00:1c.5: AER: can't find device of ID00e5

Link: https://bugzilla.kernel.org/show_bug.cgi?id=218127
Signed-off-by: Jian-Hong Pan <jhp@endlessos.org>
---
v2: Add the switch case's default condition with comment:
    "The ASPM has already been enabled by initializing
    rtl8723be_mod_params' aspm_support as 1."

v3: Rework with a PCI qurik which disables RTL8723BE PCIE's ASPM, if it
    connects to some Intel bridges, such as Skylake and Kabylake. Then,
    rtl8723be checks the PCIE ASPM is enabled, or not. If it is not,
    disables rtl8723be's aspm_support parameter.

 .../wireless/realtek/rtlwifi/rtl8723be/sw.c   |  6 ++++
 drivers/pci/quirks.c                          | 36 +++++++++++++++++++
 2 files changed, 42 insertions(+)

diff --git a/drivers/net/wireless/realtek/rtlwifi/rtl8723be/sw.c b/drivers/net/wireless/realtek/rtlwifi/rtl8723be/sw.c
index 43b611d5288d..fe9acbaa879b 100644
--- a/drivers/net/wireless/realtek/rtlwifi/rtl8723be/sw.c
+++ b/drivers/net/wireless/realtek/rtlwifi/rtl8723be/sw.c
@@ -26,6 +26,12 @@ static void rtl8723be_init_aspm_vars(struct ieee80211_hw *hw)
 	struct rtl_priv *rtlpriv = rtl_priv(hw);
 	struct rtl_pci *rtlpci = rtl_pcidev(rtl_pcipriv(hw));
 
+	/* Disable ASPM if the link control disables it */
+	if (!pcie_aspm_enabled(rtlpci->pdev)) {
+		pci_info(rtlpci->pdev, "PCIE ASPM is disabled\n");
+		rtlpriv->cfg->mod_params->aspm_support = 0;
+	}
+
 	/*close ASPM for AMD defaultly */
 	rtlpci->const_amdpci_aspm = 0;
 
diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index eeec1d6f9023..170321f4b23b 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -3606,6 +3606,42 @@ DECLARE_PCI_FIXUP_FINAL(0x1b7c, 0x0004, /* Ceton InfiniTV4 */
 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_REALTEK, 0x8169,
 			quirk_broken_intx_masking);
 
+
+static void quirk_disable_int_bridge_sub_pci_aspm(struct pci_dev *dev)
+{
+	struct pci_dev *pdev;
+	u16 val;
+
+	if (dev->bus && dev->bus->self)
+		pdev = dev->bus->self;
+	else
+		return;
+
+	if (pdev->vendor == PCI_VENDOR_ID_INTEL) {
+		switch (pdev->device) {
+		case 0x9d15:
+		/* PCI bridges on Skylake */
+		case 0xa110 ... 0xa11f:
+		case 0xa167 ... 0xa16a:
+		/* PCI bridges on Kabylake */
+		case 0xa290 ... 0xa29f:
+		case 0xa2e7 ... 0xa2ee:
+			pci_info(dev, "quirk: disable the device's ASPM\n");
+			pcie_capability_read_word(pdev, PCI_EXP_LNKCTL, &val);
+			val &= ~PCI_EXP_LNKCTL_ASPMC;
+			pcie_capability_write_word(dev, PCI_EXP_LNKCTL, val);
+			break;
+		}
+	}
+}
+
+/*
+ * Disable Realtek RTL8723BE PCIE's ASPM, if it connects to some Intel bridges,
+ * such as Skylake and Kabylake. Otherwise, the PCI AER flood hangs system.
+ */
+DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_REALTEK, 0xb723,
+			quirk_disable_int_bridge_sub_pci_aspm);
+
 /*
  * Intel i40e (XL710/X710) 10/20/40GbE NICs all have broken INTx masking,
  * DisINTx can be set but the interrupt status bit is non-functional.
-- 
2.42.1