[PATCH] PCI: qcom: Advertise hotplug with no command completion support

[Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>]

QCOM PCIe controller advertise hotplug capability in hardware but do not
support hotplug command completion. As a result, the PCI core registers
the pciehp service and issues hotplug commands that never gets completions,
leading to repeated timeout warnings and multi-second delays during boot
and suspend/resume.

Commit a54db86ddc153 ("PCI: qcom: Do not advertise hotplug capability for
IPs v2.7.0 and v1.9.0") avoided these timeouts by clearing the Hot-Plug
Capability bit entirely, which also disabled all hotplug functionality.

Instead of disabling hotplug, mark these controllers as not supporting
command completion by setting the No Command Completed Support (NCCS) bit
in the Slot Capabilities register. This prevents the PCI hotplug driver
from waiting for commands completion while still allowing hotplug-related
functionality such as Data Link Layer state change events.

Signed-off-by: Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>
---
 drivers/pci/controller/dwc/pcie-qcom.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
index 67a16af69ddc75fca1b123e70715e692a91a9135..a2924610f3625f2456a491473c135840e31bafb9 100644
--- a/drivers/pci/controller/dwc/pcie-qcom.c
+++ b/drivers/pci/controller/dwc/pcie-qcom.c
@@ -358,7 +358,7 @@ static void qcom_pcie_clear_hpc(struct dw_pcie *pci)
 	dw_pcie_dbi_ro_wr_en(pci);
 
 	val = readl(pci->dbi_base + offset + PCI_EXP_SLTCAP);
-	val &= ~PCI_EXP_SLTCAP_HPC;
+	val |= PCI_EXP_SLTCAP_NCCS;
 	writel(val, pci->dbi_base + offset + PCI_EXP_SLTCAP);
 
 	dw_pcie_dbi_ro_wr_dis(pci);

---
base-commit: 0257f64bdac7fdca30fa3cae0df8b9ecbec7733a
change-id: 20260313-hotplug-4c296595b5b8

Best regards,
-- 
Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>