Some Older AMD GPUs + Intel Alder Lake Is Causing ASPM Problems For Linux Users
Those using older AMD GPUs like the Radeon Pro WX3200 and Radeon RX 640 "Polaris" cards have reported hangs during suspend/resume when running with Intel's latest-generation Alder Lake platforms. The hang was tracked down to Active State Power Management being to blame in these combinations, so the AMDGPU Linux driver is going to disable ASPM in such configurations. When behaving correctly, ASPM is important for reducing power consumption of PCIe devices while idling.
It was last year with Linux 5.14 that AMDGPU enabled ASPM for more systems to help with power savings. ASPM in general on Linux has seen its share of issues over the years between the software and hardware. With recent hardware ASPM woes seemed to be a problem of the past, but at least with Alder Lake and select older AMD GPUs it's still causing headaches.
Intel Alder Lake with older AMD GPUs is causing issues for some Linux users.
This patch for the AMDGPU DRM driver is pending that along the AMD "Volcanic Islands" (VI) code path it will now check to see if the CPU is part of the Alder Lake family and disable ASPM if so. Newer AMD GPUs don't appear to have issues with Intel Alder Lake and again this hang issue is something that comes up during suspend/resume cycles. So if you are running Alder Lake with AMD graphics and have seen hangs in such cases, toggling ASPM or trying this patch may be worth looking into.