linux-kernel - [PATCH 3/3] PCI: dwc: Skip PME_Turn_Off and L2/L3 transition if no device is available

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Message-ID: <20251106061326.8241-4-manivannan.sadhasivam@oss.qualcomm.com>
Date: Thu,  6 Nov 2025 11:43:26 +0530
From: Manivannan Sadhasivam <manivannan.sadhasivam@....qualcomm.com>
To: lpieralisi@...nel.org, kwilczynski@...nel.org, mani@...nel.org,
        bhelgaas@...gle.com
Cc: will@...nel.org, linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org,
        robh@...nel.org, linux-arm-msm@...r.kernel.org,
        zhangsenchuan@...incomputing.com,
        Manivannan Sadhasivam <manivannan.sadhasivam@....qualcomm.com>
Subject: [PATCH 3/3] PCI: dwc: Skip PME_Turn_Off and L2/L3 transition if no device is available

If there is no device available under the Root Ports, there is no point in
sending PME_Turn_Off and waiting for L2/L3 transition, it will result in a
timeout.

Hence, skip those steps if no device is available during suspend. The
resume flow remains unchanged.

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@....qualcomm.com>
---
 drivers/pci/controller/dwc/pcie-designware-host.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
index 20c9333bcb1c..b6b8139e91e3 100644
--- a/drivers/pci/controller/dwc/pcie-designware-host.c
+++ b/drivers/pci/controller/dwc/pcie-designware-host.c
@@ -20,6 +20,7 @@
 #include <linux/platform_device.h>
 
 #include "../../pci.h"
+#include "../pci-host-common.h"
 #include "pcie-designware.h"
 
 static struct pci_ops dw_pcie_ops;
@@ -1129,6 +1130,9 @@ int dw_pcie_suspend_noirq(struct dw_pcie *pci)
 	u32 val;
 	int ret;
 
+	if (!pci_root_ports_have_device(pci->pp.bridge->bus))
+		goto stop_link;
+
 	/*
 	 * If L1SS is supported, then do not put the link into L2 as some
 	 * devices such as NVMe expect low resume latency.
@@ -1162,6 +1166,7 @@ int dw_pcie_suspend_noirq(struct dw_pcie *pci)
 	 */
 	udelay(1);
 
+stop_link:
 	dw_pcie_stop_link(pci);
 	if (pci->pp.ops->deinit)
 		pci->pp.ops->deinit(&pci->pp);
-- 
2.48.1