P-SeriesのトピックRe: Freescale P2020 CPU stuck when PCIe MSI enabled

Freescale P2020 CPU stuck when PCIe MSI enabled

jung-nanhung — Fri, 17 Jul 2015 14:14:11 GMT

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.

CONFIG_IRQ_PER_CPU=y

CONFIG_IRQ_ALL_CPUS=y

CONFIG_PCI_MSI=y

Re: Freescale P2020 CPU stuck when PCIe MSI enabled

scottwood — Tue, 28 Jul 2015 01:47:25 GMT

This may or may not be related to your problem, but CONFIG_IRQ_ALL_CPUS is inappropriate for the Freescale MPIC, and you're using a kernel that is too old to realize that.

In general, I highly recommend trying with a current kernel. There have been significant changes to the MSI code since 2.6.35, including changing the flow so that fsl_msi_cascade() no longer tries to acquire desc->lock.

Re: Freescale P2020 CPU stuck when PCIe MSI enabled

jung-nanhung — Tue, 28 Jul 2015 12:27:52 GMT

Hi Scott,

I got an errata from chip vendor . PCIe MSI can not be enabled on this PCI device because of some problems. This device can use INTx only. Yes, I had checked current Linux Kernel about MSI. It just like your description.

Thanks,