Quadro M6000 fails to connect DVI-DL device via display port, and its work around

Hi Folks,

I've problem on connecting M6000 (displayport) to Barco F50 projector (DVI-DL). I need to connect 4x Barco F50 projectors with a single M6000 display card and I'm using DVI-DL cables. There is no problem with the DVI-DL port on M6000 but I keep on having with Displayport to output DVI-DL signal. I can run 1080p@120Hz when DP port just plug in but after workstation reboot, the signal always loss (blank screen). I have to unplug and plug in the DP port again in order to re-synchronise the DVI-DL F50 projector. I tried with Sony 2K DVI-DL monitor or normal Dell DVI monitor also has the same problem. This is no such problem if I use DP to DVI-SL adaptor. Since the DVI-DL port on M6000 is performing normally with the DVI-DL cable and F50 projector, it is confirmed the cable is OK.

M6000 driver has issue on handing DP to DVI DL?

Later I set the projector EDID to 1080p@120Hz for the DVI-DL port, on Nvidia control panel, the DP port has detected it is a Barco F50 3D projector with 1080p@120Hz with DVI signal. I save the EDID information on a file via Nvidia control panel, then reload the file to permanently fixed the DP port to 1080p@120Hz with DVI signal. However, after reboot the workstation, projector displays the Windows logo then change to blank screen before the Windows login page. It seems wrong EDID information is used after windows boot up or Nvidia driver is kick in.

After login Windows and check the EDID information via Nvidia control panel, the driver shows it is sending VGA signal via the DP port instead of DVI signal, and because the DVI-DL cable just support digital signal, so there is no signal received on the projector / monitor side.

Workaround:

So instead of using DP to DVI-DL EDID information, I save the EDID information of the DVI-DL port of the M6000 card, then reload the correct EDID file to each DP port of M6000 and now all DP ports sending correct DVI-DL signal to projectors after workstation reboot.

I would like to see Nvidia to bug fix this driver problem so that I can freely change the projector resolution without the need to re-edit EDID information each time.

Regards,

Lawrence