Need clarity on PCIe MSI interrupt in device tree

[valmiki]

Hi,

I have confusion on MSI interrupt flags in PCIe documetation.

MSI interrupts are edge triggered, but i see some controllers use 
Ex:tegra <0 99 0x4>, here interrupt flags show 0x4 which means level 
sensitive as per include/dt-bindings/interrupt-controller/irq.h.

May i know why is it like this, why MSI depicted as level sensitive in 
device tree.

Regards,
valmiki