Hello,
> The remapped PCIe Root Port and the child device have PCI PM L1 substates
> capability, but they are disabled originally.
>
> Here is a failed example on ASUS B1400CEAE:
>
> Capabilities: [900 v1] L1 PM Substates
> L1SubCap: PCI-PM_L1.2+ PCI-PM_L1.1- ASPM_L1.2+ ASPM_L1.1- L1_PM_Substates+
> PortCommonModeRestoreTime=32us PortTPowerOnTime=10us
> L1SubCtl1: PCI-PM_L1.2- PCI-PM_L1.1- ASPM_L1.2+ ASPM_L1.1-
> T_CommonMode=0us LTR1.2_Threshold=101376ns
> L1SubCtl2: T_PwrOn=50us
>
> Power on all of the VMD remapped PCI devices to D0 before enable PCI-PM L1
> PM Substates by following "PCIe r6.0, sec 5.5.4".
Applied to controller/vmd, thank you!
[01/01] PCI: vmd: Set PCI devices to D0 before enable PCI PM's L1 substates
https://git.kernel.org/pci/pci/c/c8d39213cb70
Krzysztof
