I've had zero problems with S3 wake/sleep on AMD ThinkPad with FreeBSD for years. And FreeBSD uses AMD drivers pulled from Linux. How is this still a problem on Linux?
hw.acpi.lid_switch_state=S3 hw.acpi.lid_switch_state=S3In fact, it turned out that a BIOS update that happened in the middle of my issues broke sleep functionality for the whole machine for a few months, so that wasn't even my fault.