edid vs. modeline

[plesch]

Originally Posted by AaronP

You'll need to use the mode timings of the DFP's native backend mode. You can find these in Xorg.0.log if you start X with the -logverbose 6 option.

Yes, I understand. The problem, I think, is that the driver needs the EDID to know the native backend mode. However, I do not have good EDID information.

The setup is this:

7900GS -- DVI-D --> 3dp pci-card -- vga-BNC --> projector

The 3dp has an EDID but it has wrong information because the projector does not (probably can not due to BNC cabling) provide EDID information to the 3dp. So I would like to completely ignore the EDID information. For example the 3dps default preferred edid mode is 1400x1050. The projector resolution is 1280x1024.

All attempts to avoid using an EDID however resulted in a "no input" warning on the projector.

There seems something special the driver does when using edid information in addition to using the timing information. Is that possible ?

Thanks for the continued interest in this dry matter.

Andreas

[dev0]

Originally Posted by plesch

7900GS -- DVI-D --> 3dp pci-card -- vga-BNC --> projector

Just to clarify: You do take the signal from your 7900GS by the means of DVI, patch it through a mysterious '3dp pci card' so you can connect this 3dp card to your beamer by using bnc (which afaik doesn't provide any EDID info)?
If so, then why would you do that? Is there any reason not to connect the 7900gs directly to the beamer?

thx
/dev0

[plesch]

Originally Posted by dev0

Just to clarify: You do take the signal from your 7900GS by the means of DVI, patch it through a mysterious '3dp pci card' so you can connect this 3dp card to your beamer by using bnc (which afaik doesn't provide any EDID info)?
If so, then why would you do that? Is there any reason not to connect the 7900gs directly to the beamer?

Yes, that is correct. The PCI card does blending and geometry correction for curved wall displays.

[plesch]

Finally, I found that when I use an analog connection (a vga cable with adapters) the custom mode lines are used and arrive and are accepted correctly.Therefore I will not pursue the DVI-D further.

I needed to specify ConnectedMonitors "CRT" to force the analog signal even although I had a vga cable connected. That was contrary to what the readme said. Without the option the log showed that a DFP was thought to still be connected.

My lesson here is that with a DVD-D connection never try to belittle the almighty EDID It has powerful friends.