Add sysfs attributes to Endpoints and other Upstream Ports to control ASPM,
Clock PM, and L1 PM Substates. The new attributes are:
/sys/devices/pci*/.../link/clkpm
/sys/devices/pci*/.../link/l0s_aspm
/sys/devices/pci*/.../link/l1_aspm
/sys/devices/pci*/.../link/l1_1_aspm
/sys/devices/pci*/.../link/l1_2_aspm
/sys/devices/pci*/.../link/l1_1_pcipm
/sys/devices/pci*/.../link/l1_2_pcipm
An attribute is only visible if both ends of the Link leading to the device
support the state. Writing y/1/on to the file enables the state; n/0/off
disables it.
These attributes can be used to tune the power/performance tradeoff for
individual devices.
[bhelgaas: commit log, rename directory to "link"]
Link: https://lore.kernel.org/r/b1c83f8a-9bf6-eac5-82d0-cf5b90128fbf@gmail.com
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
72ea91afbf