This series adds support for enabling PCIE ASPM and for setting PCIE LTR values on devices on root ports reserved by VMD. Configuration of these capabilities is usually done by BIOS. But for VMD ports these capabilities will not be configured because those ports are not visible to BIOS. For future products, post Alder Lake, the hardware team has agreed to do this enabling in BIOS. But this will not apply to current products, so this work around is provided for them. Without this, laptops running in VMD mode will not be able to power gate roots ports, resulting in higher power consumption. Since V4 we have more information from the BIOS team as to why BIOS needs to program device LTRs. This is something that should be done by devices, but there are many that don't provide LTR values causing them to block SoC level power management. BIOS sets an initial default LTR to account for such devices. This SoC specific value is the maximum latency required to allow the SoC to enter the deepest power state. David E. Box (2): PCI: vmd: Add vmd_device_data PCI: vmd: Configure PCIe ASPM and LTR Michael Bottini (1): PCI/ASPM: Add ASPM BIOS override function drivers/pci/controller/vmd.c | 104 ++++++++++++++++++++++++++--------- drivers/pci/pcie/aspm.c | 54 ++++++++++++++++++ include/linux/pci.h | 7 +++ 3 files changed, 139 insertions(+), 26 deletions(-) -- 2.25.1
