Customer support: Problems with DVI connected monitor

[Olivier]

Yesterday I got an email from someone who dowloaded my game's demo. He's telling me that the game displays only a black screen, but that he can hear the audio (same problem occurs with Doom3). This only happens when he's using his DVI cable, everything was ok when he plugged his standard video cable.

I'm not tech savvy at all, and didn't heard much about DVI before. Do you guys/gals were already confronted to such a problem? What advice could I give him?

PS: Sorry if this is the wrong forum.

[C_Coder]

Make sure that he is not using Multihead display. It can be that the card is outputting the same signal on both the VGA and the DVI ports. Now when DX starts up, it uses the preferred device which is the VGA port. These are seen as different adapters even in a single card. Make sure that you have a selection in your video options to choose the adapter that you want to use.

I have a dualhead card myself and same thing happens. Only you have to choose the correct adapter which in my case the DVI port is adapter 1 while the VGA port is adapter 0.

May this help you...

[Robert Cummings]

Most TFT's now use DVI instead of DB15. DVI is just a port at the back of the monitor and the graphics card. It seems he might have multiple monitors set up. We need more information.

[Donavon Keithley]

Yeah I agree -- it sounds like there is a logical device associated with each port.

If so, what he probably wants is to switch the primary monitor to the DVI port. Assuming Windows XP, you'd go into the Display control panel, 'Settings' tab, click the rectangle that doesn't have 'Use this device as the primary monitor' checked (most likely #2 since it's the DVI port), and then click that checkbox.

This would also imply that his desktop is being extended across both displays -- not a good idea if you only have one monitor. :) To fix that, click on the other monitor, the one representing the analog port, and uncheck 'Extend my Windows desktop onto this monitor.'

Actually though, if that's the case, then this person likely has problems with apps starting up off-screen, preferring the primary monitor. Also desktop icons gravitate towards the primary display, Alt-Tab shows up on the primary display, etc.

But it's the only explanation I can think of that would explain this. If the driver were set up to 'clone' the desktop to each port then there would be only one logical device and games would run fine using either cable.

[Olivier]

Thanks guys for your responses. I'll ask him if he's using a dualhead card.
I'm not sure if I can add a video adapter selection feature in my game, I'm a bit stucked by.. MMF. :o
My game defaults to fullscreen (640*480), but he might be able to see the game if windowed. As a small test, I'll tell him to modify the INI file so the game launches in windowed mode.