Refer to PCIe r6.0, sec 5.2, fig 5-1 Link Power Management State Flow Diagram. Both L0 and L2/L3 Ready can be transferred to LDn directly. It's harmless to let dw_pcie_suspend_noirq() proceed suspend after the PME_Turn_Off is sent out, whatever the LTSSM state is in L2 or L3 after a recommended 10ms max wait refer to PCIe r6.0, sec 5.3.3.2.1 PME Synchronization. The LTSSM states of i.MX6QP PCIe is inaccessible after the PME_Turn_Off is kicked off. To handle this case, don't poll L2 state and add one max 10ms delay if QUIRK_NOL2POLL_IN_PM flag is existing in suspend. Main changes in v4: - Add one patch[1/6] to remove the L1SS check during L2 entry. - Update the code comments of 2/6 patch and commit description of 6/6 patch. - Add background to 5/6 to describe why skip PME_Turn_off message when no endpoint device is connected. v3:https://patchwork.kernel.org/project/linux-pci/cover/20250818073205.1412507-1-hongxing.zhu@xxxxxxx/ Main changes in v3: - Adjust the patch sequence to avoid the build break. - Update the commit message. v2:https://patchwork.kernel.org/project/linux-pci/cover/20250618024116.3704579-1-hongxing.zhu@xxxxxxx/ Main changes in v2: Add the following two patches. - Skip PME_Turn_Off message if there is no endpoint connected. - Don't return error when wait for link up. v1:https://patchwork.kernel.org/project/linux-pci/cover/20250408065221.1941928-1-hongxing.zhu@xxxxxxx/ drivers/pci/controller/dwc/pcie-designware-host.c [PATCH v4 1/6] PCI: dwc: Remove the L1SS check before putting the [PATCH v4 2/6] PCI: dwc: Don't poll L2 if QUIRK_NOL2POLL_IN_PM is [PATCH v4 3/6] PCI: imx6: Don't poll LTSSM state of i.MX6QP PCIe in [PATCH v4 4/6] PCI: imx6: Don't poll LTSSM state of i.MX7D PCIe in PM [PATCH v4 5/6] PCI: dwc: Skip PME_Turn_Off message if there is no [PATCH v4 6/6] PCI: dwc: Don't return error when wait for link up in drivers/pci/controller/dwc/pci-imx6.c | 4 ++++ drivers/pci/controller/dwc/pcie-designware-host.c | 61 +++++++++++++++++++++++++++++++++++-------------------------- drivers/pci/controller/dwc/pcie-designware.h | 4 ++++ 3 files changed, 43 insertions(+), 26 deletions(-)
