In BIOS, there is a setting that allows the OS to control the ASPM of PCIe devices, including the USB ports.
However, when I make these changes, only some of the USB ports come under control of the OS. If I examine the PCI Configuration Space, several of the registry values indicate that ASPM is disabled.
The root ports that are obeying BIOS are the following. When I change their controls to L0sL1, the registry value changes from 40 (disabled) to 43 (L0sL1)
00:1c.0 PCI bridge: Intel Corporation 200 Series PCH PCI Express Root Port #1
00:1c.2 PCI bridge: Intel Corporation 200 Series PCH PCI Express Root Port #3
00:1d.0 PCI bridge: Intel Corporation 200 Series PCH PCI Express Root Port #9
The following do NOT obey BIOS instructing them to be controlled by the OS. When I change their controls to L0sL1, the registry value does not change, they remain 40 (disabled)
00:1c.4 PCI bridge: Intel Corporation 200 Series PCH PCI Express Root Port #5
00:1c.6 PCI bridge: Intel Corporation 200 Series PCH PCI Express Root Port #7
Likewise endpoints for these two do not obey BIOS, and remain 40 no matter what the BIOS setting is.
04:00.0 USB controller: ASMedia Technology Inc. Device 2142
05:00.0 USB controller: ASMedia Technology Inc. Device 2142