PCIe on Arria 10 works on one host machine and doesn't work on other host

[Altera_Forum]

Hi, 

 I have two Arria 10 GX dev. board, let me call then A1 and A2 for simplicity and also I have two host machines, M1 and M2. Both the A1 and A2 boards are detected as a PCIe device after enumeration on Machine M1, while on Machine M2, only A1 is getting detected as a PCIe device but not A2. Both A1 and A2 have the same bit files on them, they have the same switch settings and I have tested them on the same PCIe slots on both M1 and M2. I'm not sure what else is missing. If anyone else has faced the same issue or know what could be missing, please provide me some help!  Thanks

[Altera_Forum]

How are your timing constraints? It's possible that the timing requirements for the design are on the edge and so you might have issues with silicon to silicon variation between devices. Make sure all of your timing constraints are in place and that timing requirements are met at all four corners  

 On the machine that only one enumerates on, does it come up with the correct link speed? E.g. if you are targrtting gen 3, do you get gen3 or gen1. That would indicate a signalling issue in which the variation between silicon might just allow one of the boards to enumerate at a lower than targetted speed but not the other.  Another option is power - one of the dev kits might be drawing a little more than the other and if the slot can't keep up it could be browning out. You could try using an external supply of not already doing so to give it a boost. Alternatively measure the 12V and 3.3V lines of the PSU with a scope to make sure they are clean and within spec.

[Altera_Forum]

Hi, 

 Thanks for the response. It worked finally. Timing is fine at all 4 corners. The issue was with power. I used a different ATX source from the host machine this time.

[Altera_Forum]

Hi, 

 I have connected my HOST (Workstation Desktop PC ) to arria10 SOC development kit through a PCIe cable Connector. After Programming example design (PCIe AVMM DMA (AN690.pdf)) (EPCQ or sof) any way of configuration in Arria10 soc kit. When I poweron My Workstation PC, The kit does not show up in device manager. I tried for simple Arria10 PCIe hard ip by exposing its main signals(Reset, Tx, Rx, Refclk). Here also it does not show up in device manager.  My host Desktop PC and Arria 10 SOC kit are connected by PCIe cable, where I have removed Power lines.  I am programming by giving external power supply and once done LED goes high I switch on my Host PC. attached snapshots of my hardware setup.  and modified example design PCIe AVMM DMA and simple PCIe arria 10 hard ip design .  Please have a look and give inputs where I am going wrong.  Thanks, Kamal chandra