I had an idea that you might be be able to do this via /proc but a test in my environment (Linux 2.4, GForce 2 MX) was disppointing although I was able to retrive the boundary address for the vid card address space. Unfortunately I am using the NON-OPENSOURCED (sheesh) NVidia Drivers so I couldn't look at the driver source for clues.

But I suspect even if you do have the register addresses in hand for you card you will have resort to 'C' to get grab register info directly or interrogate the driver.

Update: Erik Hensema is right on. I am so used to thinking in terms my own dev environment where I am grand poobar :). Registers of interest will as Eric points out reside in kernel space and require privileged access. To expand on Eric's idea you could look at Xconfigurator( is this a Red Hat Only thing?) source since it does probe for monitor type.

mitd-Made in the Dark
'Interactive! Paper tape is interactive!
If you don't believe me I can show you my paper cut scars!'