I tested the code on Voodoo Banshee (16 MB SDRAM, PCI  bus and 16 MB SGRAM, AGP bus), Voodoo 3 1000 (16 MB SDRAM, PCI bus), and Voodoo 5 5500 AGP (AGP bus; the original “monster” gamer graphics card) with Xubuntu 16.04.5 (X Server 1.19.6). Standby resume does not work.