Re: [PATCH v3] dma-mapping: skip USB devices when configuring DMA during probe

[Christoph Hellwig]

I think the root problem is that the code added by
" of/acpi: Configure dma operations at probe time for platform/amba/pci bus
devices"

is completely bogus and needs to be reverted.  We can't simply iterate
over all devices in the system and set up dma for them.  We'll need
to ask the firmware / OF what root port this applies to and only
apply it to those buses.

Note that the current code checks for a OF or ACPI node already,
so we should start by refining these checks.