Hi folks!

I'm wondering if RiscBSD is treating the separate/common sync issue
differently than RISC OS.
The story goes like this:
Recently, I bought a cheap PC, mainly to run FreeBSD on it (and to play
games too :-) ).
I tried to connect it to the second input of the monitor, a 4-plug BNC.
This doesn't work because the PC won't output composite sync as needed by
the BNC input, the screen will always rotate thorugh vertically.

So I swapped the two computers. PC works fine now because the other
connector on the monitor, a 9-pin D-Sub, has separate sync lines.
For the Risc PC I looked up the pin assignment in the Welcome Guide
(IIRC). It says that you should feed back HSync from pin 13 to pin 11
(Monitor ID 0) to tell the computer to output CSync on the VSync line (pin
14). I did so and it works well for RISC OS, no difference to a connection
on the D-Sub input.
But in RiscBSD, the screen rotates through vertically because the monitor
can't lock on the vertical sync! Even if I turn the vhold adjuster on
the monitor, the screen still won't lock. My self-compiled kernel has the
same mode compiled in that I'm using in RISC OS. And I tried an install
kernel too - same result.

Questions:
How is the switching between separate and common sync done by the Risc PC?
I would assume it's hardware but I`m not so sure because there is a bit in
the VIDC control register to control this. (I only have a datasheet for
the old VIDC but I don't think it was dropped in the VIDC20.)
Maybe RISC OS checks pin 11 of the VGA connector and sets the bit in the
VIDC control register accordingly? Would seem like a strange way to me,
though. Can somebody with a tech manual please look where pin 11 on the
VGA connector is going?
If so, maybe RiscBSD doesn't do this?
What would be a good place to set this bit from the RiscBSD kernel? I
could hardwire this in my custom kernels.
Does anybody have another hypothesis why I`m getting a stable picture in
RISC OS but not in RiscBSD?

I hope somebody can help me.

Thanks, Markus