On Wed, Dec 01, 2021 at 03:52:02PM +0100, Thomas Gleixner wrote: > So we really can go and create a MSI irqdomain and stick the pointer > into stdev->dev.irqdomain. The parent domain of this irqdomain is > > stdev->pdev.dev.irqdomain->parent It can work (pending some solution to the iommu stuff), but IMHO it is strange/hacky to put HW objects like irqdomain on what is a character struct device with a set major/minor in dev->devt and associated struct cdev. Conceptually it makes no sense to me, cdevs are software constructs, they should never go into HW areas.. Jason