Where does 8.0/amd64's X server get resolution from?

[Mouse <mouse%Rodents-Montreal.ORG@localhost>]

I'm working on a commercial turnkey product, trying to migrate it to
NetBSD 8.0.  (It started out on DOS and had an intermediate version
running on NetBSD 5.2.)

One of the issues I'm trying to address is that it is designed for a
1280x1024 display, but the X server doesn't always start 1280x1024,
perhaps most notably if no monitor is connected at boot time.  Under
5.2, I dealt with this by adding options to the X server to,
essentially, capture and replay DDC data.  But, under 8.0, while the X
server has more or less the same code, it never runs, even if I boot -c
and disable i915drmkms (which, on that hardware, is enough to make the
console stay in text mode instead of switching to text-via-graphics).
I know this because I've added code at that point in the X server
(external/mit/xorg-server/dist/hw/xfree86/vbe/vbe.c), code that leaves
traces.

I could probably figure out where the 8.0 X server is getting its DDC
info, or moral equivalent, to override it.  But it occurs to me that
it's likely someone here already knows the answer and might perhaps be
willing to save me the digging necessary to figure that out.  Or,
perhaps, is there something else I can disable at boot (or kernel
config) time that will make the X server fall back to using the vbe
code I already put hooks into?

This can, in a sense, be fixed up after the fact with RandR requests
(such as are issued by xrandr commands).  I am prepared to resort to
that if necessary, but it would be significantly more convenient to
have a way to make the X server start in 1280x1024 regardless of what
is or isn't connected at X start, or was or wasn't connected at boot.

Anyone?

/~\ The ASCII				  Mouse
\ / Ribbon Campaign
 X  Against HTML		mouse%rodents-montreal.org@localhost
/ \ Email!	     7D C8 61 52 5D E7 2D 39  4E F1 31 3E E8 B3 27 4B