The P2020 CPU is running in SMP mode based on Linux 2.6.35 Kernel. The PCIe is configured x2 , 256 bytes payload and relaxing ordering for our PCIe deice. It is good when MSI is disabled. But CPU will stuck after running for a while if MSI is enabled. It is like a spin_lock in the "fsl_msi_cascade " function according to debug info. Below Linux configuration is enabled.