When the kernel module is loaded I get a "xdma_error_detected: dev 0xffff9913b43d9000,0xffff9913b3d76000, frozen state error, reset controller" message. the kernel then proceeds to stop engines and set the devices offline, do a slot reset, then set the device online again. When I try to use the reg_rw tool, I always return 0xffffffff.
This error only happens when I have my PCIe card in a X1 slot. When it is in a X16 slot, everything works as expected.