Hello
I am facing a problem when I connect a PCIe 4x card on the PCIe 16x slot of Optiplex 755 desktops.
This card was developed by us for image and video acquisition, and it includes a Virtex-5 FPGA which uses the PCIe IP provided by Xilinx. This card is in use since 5 years and it works correctly on several kinds PCs including the Dell Optiplex 740.
When I plug this card on an Optiplex 755, the PC is not able to boot, the power supply starts and stops several times, and at the end the PC remains with the power on. Nothing is displayed on the display when the PC tries to boot.
Front panel diagnostic lights 2 and 4 are ON when the PC hangs, which is supposed to indicate a graphics card issue (Optiplex user guide), I have then supposed that the PC considers my board as a graphics card and modified the BIOS setup to use the onboard card, but that didn’t fixe the issue.
I have then tried with a couple of PCIe 1x cards on the x16 slot and they all work fine, I have even tried with my card on which I’ve disconnected data links 2, 3, and 4 and it worked perfectly when I only the first link is connected. I have also tried with a 16x graphics card and it works.
The last test I’ve done was to use a an external power supply for my card , in this case my board works fine with the 4 links if I start the PC and I boot windows XP first before I power up the card. No problem to install the drivers once the OS has started.
As a conclusion, I have the feeling that the problem is with the BIOS, which considers that any board inserted in the x16 slot with more than 1 data link connected is a graphics card, and if it is not the case, the BIOS hangs. I have of course flashed the last version of the BIOS but no improvement.
Just a last point, I have tested several acquisition cards on several Optiplex 755.
Would anyone have an idea?
Thanks for your help
Naim