From 774820b362b07b903354470f9372d528b327a3e5 Mon Sep 17 00:00:00 2001 From: Bjorn Helgaas Date: Fri, 7 Apr 2023 12:19:46 -0500 Subject: [PATCH] PCI/EDR: Add edr_handle_event() comments EDR documentation is a bit sketchy. Add a couple comments to edr_handle_event() about the devices involved. Link: https://lore.kernel.org/r/20230407215259.GA3825733@bhelgaas Signed-off-by: Bjorn Helgaas Reviewed-by: Kuppuswamy Sathyanarayanan --- drivers/pci/pcie/edr.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/drivers/pci/pcie/edr.c b/drivers/pci/pcie/edr.c index 87734e4c3c20..5f4914d313a1 100644 --- a/drivers/pci/pcie/edr.c +++ b/drivers/pci/pcie/edr.c @@ -151,9 +151,18 @@ static void edr_handle_event(acpi_handle handle, u32 event, void *data) if (event != ACPI_NOTIFY_DISCONNECT_RECOVER) return; + /* + * pdev is a Root Port or Downstream Port that is still present and + * has triggered a containment event, e.g., DPC, so its child + * devices have been disconnected (ACPI r6.5, sec 5.6.6). + */ pci_info(pdev, "EDR event received\n"); - /* Locate the port which issued EDR event */ + /* + * Locate the port that experienced the containment event. pdev + * may be that port or a parent of it (PCI Firmware r3.3, sec + * 4.6.13). + */ edev = acpi_dpc_port_get(pdev); if (!edev) { pci_err(pdev, "Firmware failed to locate DPC port\n"); -- 2.11.0