I was going to say, what Linux user can even FIND an S3 GPU to use? Outside of some very ancient IGPs in P4/Athlon XP era hardware their stuff is exceedingly hard to find.
A few years ago I went looking for one of their dedicated PCIe GPUs as they had supposedly released 2 models that where supposed to be competitive with the low end from AMD and NVidia. After a week of searching and finding no shop that carried them and only finding one small time review site that was even sent these GPUs I gave up.
I'm curious where VIA's x86 processors are used as well.
Here. I had a laptop with a C3-2 (ECS G320) and I stil use a VIA C7 mainboard (miniITX) from Jetway. It's quite okay besides the mediocre GPU support. Low energy at their time for sure. And crypto accel. So nice for fileservers and with a good GPU they'd also be fine at HTPC but ... the GPU.
There is still quite a bunch of miniITX, pico/nanoITX and industrial boards featuring these chips.
I still own mainboards with and dedicated cards for ISA slot. Good old times where you had even the RTclock on a card ;-). If something was broken or too old you just replaced it or add something else. Very modular unlike today's stuff. Not enough slots. And I don't want PCIe. At least not for a stupid NIC that would even run full speed in an ISA slot. I have so many PCI cards why re-buy them in PCIe?
2D accel on VIA chips did also not always work. I had some releases that were okay on MPEG2 decoding, but also some where it was messed up. Sometimes it would freeze the whole box. Some drivers (libv's old one) wouldn't build with recent X and so on.