Monitor on DVI-I not detected

Matthias Hopf mhopf at
Fri Apr 13 03:40:47 PDT 2007

On Apr 13, 07 11:30:23 +0200, Matthias Hopf wrote:
> The current driver doesn't detect a CRT monitor that is attached to
> DVI-I with a DVI-I to VGA adapter (Port1: Monitor -- NONE). That results
> this monitor remaining black if something is connected to the secondary
> output, or if MonitorLayout is set to AUTO,CRT.
> The strange thing is - it does work with an LCD display, both with DVI-D
> (Monitor -- TMDS) and with the DVI-I to VGA adapter (Monitor -- CRT).
> In both cases a monitor is detected.  The used CRT is known to behave
> well (Vision Master Pro 450), though it is pretty old.

I should read more code...

        /* This doesn't seem to work reliably (maybe worse on some OEM cards),
           for now we always return false. If one wants to connected a
           non-DDC monitor on the DVI port when CRT port is also connected,
           he will need to explicitly tell the driver in the config file
           with Option MonitorLayout.

The code that is disabled in that function looks pretty bitrotten as
well, it only has one code path for R200 and one for "other" (R100?
R300? R400?) hardware. It apparently hasn't been enabled for a long

Any caveats with enabling the currently disabled code? Except that it
might turn on a CRTC even if a monitor is *not* present? Or may it crash
the hardware? Probably nobody knows ;)



Matthias Hopf <mhopf at>      __        __   __
Maxfeldstr. 5 / 90409 Nuernberg   (_   | |  (_   |__          mat at
Phone +49-911-74053-715           __)  |_|  __)  |__  R & D

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