On Fri, Mar 26, 2021 at 12:03:03PM +0000, Robin Murphy wrote: > This might happen to work out, but is far from correct. Just wait until you > try it on a platform where the USB controller is behind an IOMMU... > > It looks like something is more fundamentally wrong here - the device > passed to DMA API calls must be the actual hardware device performing the > DMA, which in USB-land I believe means the controller's sysdev. The shiny new usb_intf_get_dma_device API provides the device to use.
