| Message ID | 20250613124839.2197945-12-cassel@kernel.org |
|---|---|
| State | New |
| Headers | show |
| Series | PCI: dwc: Do not enumerate bus before endpoint devices are ready | expand |
diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c index c789e3f85655..9b12f2f02042 100644 --- a/drivers/pci/controller/dwc/pcie-qcom.c +++ b/drivers/pci/controller/dwc/pcie-qcom.c @@ -1564,6 +1564,7 @@ static irqreturn_t qcom_pcie_global_irq_thread(int irq, void *data) writel_relaxed(status, pcie->parf + PARF_INT_ALL_CLEAR); if (FIELD_GET(PARF_INT_ALL_LINK_UP, status)) { + msleep(PCIE_RESET_CONFIG_WAIT_MS); dev_dbg(dev, "Received Link up event. Starting enumeration!\n"); /* Rescan the bus to enumerate endpoint devices */ pci_lock_rescan_remove();
Per PCIe r6.0, sec 6.6.1, software must generally wait a minimum of 100ms (PCIE_RESET_CONFIG_WAIT_MS) after Link training completes before sending a Configuration Request. Prior to 36971d6c5a9a ("PCI: qcom: Don't wait for link if we can detect Link Up"), qcom used dw_pcie_wait_for_link(), which waited between 0 and 90ms after the link came up before we enumerate the bus, and this was apparently enough for most devices. After 36971d6c5a9a, qcom_pcie_global_irq_thread() started enumeration immediately when handling the link-up IRQ, and devices (e.g., Laszlo Fiat's PLEXTOR PX-256M8PeGN NVMe SSD) may not be ready to handle config requests yet. Delay PCIE_RESET_CONFIG_WAIT_MS after the link-up IRQ before starting enumeration. Reviewed-by: Damien Le Moal <dlemoal@kernel.org> Reviewed-by: Wilfred Mallawa <wilfred.mallawa@wdc.com> Fixes: 82a823833f4e ("PCI: qcom: Add Qualcomm PCIe controller driver") Signed-off-by: Niklas Cassel <cassel@kernel.org> --- drivers/pci/controller/dwc/pcie-qcom.c | 1 + 1 file changed, 1 insertion(+)