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From:   Xiaochun Lee <lixiaochun.2888@163.com>
To:     linux-pci@vger.kernel.org
Cc:     bhelgaas@google.com, linux-kernel@vger.kernel.org,
        Xiaochun Lee <lixc17@lenovo.com>
Subject: [PATCH v1] PCI/DPC: Skip EDR init when BIOS disable OS native DPC
Date:   Wed, 27 Jul 2022 19:05:57 +0800
Message-Id: <1658919957-53006-1-git-send-email-lixiaochun.2888@163.com>
Precedence: bulk

From: Xiaochun Lee <lixc17@lenovo.com>

ACPI BIOS may disable OS native AER and DPC support to notify OS
that our platform doesn't support AER and DPC via the _OSC method.
BIOS also might leave the containment be accomplished purely in HW.
When firmware is set to non-aware OS DPC, we skip to install
EDR handler to an ACPI device.

Signed-off-by: Xiaochun Lee <lixc17@lenovo.com>
---
 drivers/pci/pcie/edr.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/drivers/pci/pcie/edr.c b/drivers/pci/pcie/edr.c
index a6b9b47..97a680b 100644
--- a/drivers/pci/pcie/edr.c
+++ b/drivers/pci/pcie/edr.c
@@ -19,6 +19,17 @@
 #define EDR_OST_SUCCESS			0x80
 #define EDR_OST_FAILED			0x81
 
+static int pcie_dpc_is_native(struct pci_dev *dev)
+{
+	struct pci_host_bridge *host = pci_find_host_bridge(dev->bus);
+
+	if (!dev->dpc_cap)
+		return 0;
+
+	return pcie_ports_dpc_native || host->native_dpc;
+}
+
+
 /*
  * _DSM wrapper function to enable/disable DPC
  * @pdev   : PCI device structure
@@ -212,6 +223,11 @@ void pci_acpi_add_edr_notifier(struct pci_dev *pdev)
 		return;
 	}
 
+	if (!pcie_dpc_is_native(pdev) && !pcie_aer_is_native(pdev)) {
+		pci_dbg(pdev, "OS doesn't control DPC, skipping EDR init\n");
+		return;
+	}
+
 	status = acpi_install_notify_handler(adev->handle, ACPI_SYSTEM_NOTIFY,
 					     edr_handle_event, pdev);
 	if (ACPI_FAILURE(status)) {
-- 
1.8.3.1