AMDGPU Appears Ready To Flip On ASPM For More GPUs To Help With Power Savings

With Linux 5.13 AMD began enabling ASPM by default in the AMDGPU DRM driver for Navi 1x, Vega, and Polaris GPUs. Looking ahead to potentially 5.14, AMD appears to be ready to flip on this power-savings feature for the Radeon RX 6000 series (Navi 2x) along with older pre-Polaris GPUs too.

PCI Express Active State Power Management (ASPM) has been a tricky situation on Linux especially for years. Due to quirky motherboards as well as some problematic PCIe cards, this feature while part of the PCI Express standard hasn't often been used by default due to various problems that can come up with quirky hardware as well as the latency when returning from the ASPM state. When working nominally, ASPM is designed to provide active-state link power management to cut power to the PCIe link when otherwise idle and can often deliver measurable power savings for laptops and desktops.

While the initial ASPM support in AMDGPU worked its way to be enabled by default for Navi 1x / Vega / Polaris, it looks like AMD is now comfortable enabling it for more GPUs moving forward. There is a patch sent out today to enable ASPM by default. While the patch message is light, it's enabling Active State Power Management by default for more GPUs from the RX 6000 "Sienna Cichlid" GPUs while on the older spectrum back through Volcanic Islands.

It will be interesting to see how this plays out for power-savings and will be working on some tests -- now for the GPUs on Linux 5.13 and then once this work lands for those affected GPUs.