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PCI: qcom: Clear Attention Button Present in Slot Capabilities

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Qcom PCIe Root Ports advertise the Attention Button Present (ABP) bit in
the Slot Capabilities register, but the slots have no attention button.

When ABP is set, pcie_enable_notification() in the pciehp driver enables
the Attention Button Pressed interrupt (ABPE) and leaves the Presence
Detect Changed interrupt (PDCE) disabled. As a result, presence detect
changes are never reported, and surprise hot-plug detection that relies on
Presence Detect Changed events does not work.

Clear the Attention Button Present (ABP) bit in the Slot Capabilities
register so pciehp Presence Detect Changed events work.

Signed-off-by: Qiang Yu <qiang.yu@oss.qualcomm.com>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
[bhelgaas: say what the patch does in the commit log]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Tested-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com> # X1E80100 CRD
Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Link: https://patch.msgid.link/20260713-b4-clear_abp_0713-v2-2-4f0333a98d4e@oss.qualcomm.com
This commit is contained in:
Qiang Yu 2026-07-13 00:42:51 -07:00 committed by Bjorn Helgaas
parent 9f46f9d696
commit 65ccb2203e
1 changed files with 6 additions and 0 deletions
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6
drivers/pci/controller/dwc/pcie-qcom.c
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@ -372,6 +372,12 @@ static void qcom_pcie_set_slot_cap(struct dw_pcie *pci)
*/
val = readl(pci->dbi_base + offset + PCI_EXP_SLTCAP);
val |= PCI_EXP_SLTCAP_NCCS;
/*
* Qcom PCIe Root Ports do not support Attention Button, so clear
* Attention Button Present in Slot Capabilities.
*/
val &= ~PCI_EXP_SLTCAP_ABP;
writel(val, pci->dbi_base + offset + PCI_EXP_SLTCAP);
dw_pcie_dbi_ro_wr_dis(pci);