MPC8641D PCI-Express problem

[Marco Stornelli <marco.stornelli@coritel.it>]

Hi,

do you remember my problem with the pci-express? I have an mpc8641d_hpcn 
(rev. 2.0) board connected via pci-express with the Xilinx ML555 
evaluation board. I'm using the 2.6.24 kernel. I'm observing this 
strange behavior:

1) I turn on the board and I stop the U-boot
2) I load the FPGA microcode
3) I start the system
4) I load the driver module and I read a version register in the FPGA
5) The system crashes with a "machine check exception: transfer error 
ack signal"
6) reboot
7) same procedure (without load the FPGA again)
8) now I can read the registers!

If I repeat the procedure again it doesn't work anymore. I think it's a 
problem with pci-express controller. Have you got any suggestions?

Thanks.

Marco