FreeBSD and DVI LCD monitors

Louis LeBlanc freebsd at
Sun Jul 4 05:37:24 PDT 2004

On 07/04/04 12:14 AM, 3BSD sat at the `puter and typed:
> I have been trying for several days to get XFree86 going with my LCD
> monitor, but to no luck.
> Hardware:
> GeForce FX 5200
> BenQ FP991 19" LCD monitor with DVI-S and HD-15 connectors.
> I shelled out a little extra for this monitor *specifically* for its
> DVI port, but it just simply won't work with FreeBSD. Slackware Linux
> 10 runs fine on the monitor on the same computer using X.Org server.
>  I read on google search results that DVI monitors need a Refresh rate
> of 60Hz. At first I did not know which one were they talking about,
> which happened to by Vertical Sync, so I set that to 60 and did a
> startx, nothing.
> Monitor displays a "no input signal" messages and the light blinks.
> Then I installed nvidia drivers and tried, it got worse, I could not
> get my console back, while the system had not crashed, the display
> just would not come back, so I had to do a blind reboot.
> I then read somewhere that with some monitors, there is a problem with
> DDC, they lie about their digital sync rates suitable for display on
> the DVI port and report the analog port settings instead. I found out
> that I had to add:
> Option       "NoDDC"       "1"     (or "true")
> to XFree86. I added the line, typed startx and was dissapointed yet
> again. Same "no input signal" message on the monitor again.
> I figured that if server worked under Linux, then it should work
> with FreeBSD without problems, but I can't even try that since
> port will refuse to install (already sent an e-mail in that regard to
> this group).
> Can anyone show me a way out of this mess? Should I try an ATi
> graphics card? Is there some configuration blunder that I'm making?

The first thing to do is check /var/log/XFree86.log to see what the
problem really is.  It isn't always crystal clear, but it's usually
very useful.

I have the same card, 128MB DDR NVidia GeForce FX5200.  I just got
XFree86 up and working on a Dell E172FP monitor.  Not sure how similar
the monitor is, but my experience was that the screen section was at
least as important.  Just in case it helps, here's my Card0, Monitor0,
and Screen0 sections from XF86Config:

# Monitor section
Section "Monitor"
    DisplaySize  330   240 # mm
    Identifier   "Monitor0"
    HorizSync    31.5 - 79.0
    VertRefresh  50.0 - 70.0
    ModelName    "DELL E172FP"
    VendorName   "DELL"
    # Option     "DPMS"
# Graphics device section
Section "Device"
    Identifier  "Card0"
    Driver      "nv"
    # ChipSet     "GeForce DDR"
    Card        "nv GeForce DDR"
    VideoRam    131072
    VendorName  "NVIDIA"
    BoardName   "GeForce2 Go"

# Screen section
Section "Screen"
    Identifier   "Screen0"
    Device       "Card0"
    Monitor      "Monitor0"
    DefaultDepth 24

    Subsection "Display"
        Depth    24
        Modes    "1280x1024" "1024x768"
        ViewPort 0 0

This is working great so far.  I still want to get the monitor sync
rates tweaked out a bit, but the rates in that canned config were
within the specified tolerances for the monitor, so they went in to

Get online and check the sync rates on your monitor.  Then just make
sure you choose a canned config that falls under those maximums.  That
will do to start, then you can (carefully) start to tweak your config

Louis LeBlanc               leblanc at
Fully Funded Hobbyist, KeySlapper Extrordinaire :)                     Ô¿Ô¬

bug, n:
  An elusive creature living in a program that makes it incorrect.
  The activity of "debugging", or removing bugs from a program, ends
  when people get tired of doing it, not when the bugs are removed.
    -- "Datamation", January 15, 1984

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