Seasidepeter wrote:
> On 01/06/2012 15:11, pjp wrote:
>> In article<>,
>> says...
>>>
>>> I have two monitors and a tv connected to my graphics card (nvidia
>>> gtx460). One
>>> monitor (Benq) uses a DVI port and is set as the primary display. The
>>> other (an
>>> old relysis) shares the vga port with the tv (I have to swap plugs,
>>> because the
>>> relysis doesn't handle dvi properly).
>>>
>>> The problem: the PC always boots to the monitor on the vga socket,
>>> whether it's
>>> the tv or the relysis. Which means I'm sat staring at a blank Benq
>>> while the tv
>>> in the other room is asking me choose an OS.
>>>
>>> How can I get the PC to boot to the dvi port instead? I see nothing
>>> in the BIOS
>>> on the Asus M2N68 motherboard to control it.
>>>
>>> Help, anyone?
>>
>> ??? MY NVidia 4850 activates both outputs during boot, e.g. it's seen on
>> both screens. They become "separate" sometime during the OS boot
>> process. Mind you I have all three connected at once, e.g. two monitors
>> and a tv.
>> The displays are duplicated across the two last "active" monitors even
>> if one was the tv.
> Yes, that's what I'd hoped for...but sadly, it boots to the vga
> connection first. The 460 will only handle two connections at once
> despite having three outputs - and the dvi (my main display) doesn't cut
> in until windows itself has booted.
>
> I was hoping there'd be a setting I'd missed in BIOS, or at a low level
> for the card itself...
Does your GTX460 have two DVI ? And you're using a DVI to VGA adapter
on one of them ?
If that was the case, perhaps you could switch connectors at the faceplate,
on the assumption that the DVI connectors are checked in order for the
presence of a display. (Then, in each OS, you'll need to "reverse" the position
of the "left" and "right" displays, if using dual monitors in span.)
Video cards have impedance sensing. On the VGA port, a 75 ohm load
can be detected on RGB. On DVI, the signals are differential and
a 100 ohm load is expected across each signal pair. I wouldn't have
expected a problem detecting a DVI. Maybe it is something to
do with the display not having DDC EDID ? There is a serial clock and
data channel on the monitor cable, used to communicate resolution info
from the monitor to the computer.
http://en.wikipedia.org/wiki/Display_Data_Channel
You can check the EDID info from each monitor, with this. This tool
is supposed to do a real time check (not rely solely on cached info),
and if a display is missing EDID info, you might be able to determine
that.
In the example here, there are two "real time" entries showing.
http://www.entechtaiwan.com/util/moninfo.shtm
Just a guess,
Paul