On Sun, Jun 26, 2005 at 09:53:51PM +0200, Manuel Bouyer wrote:
> 
> Right now, bus_dma(9) because it only knows the limitations of the bus
> (e.g. the 16MB limit for ISA, or 4GB limit for 32bit PCI).

Why not change the attachments for devices with broken bus interfaces
to hang them off a fake "bus" that enforces the relevant DMA restrictions?

After all, logically that's precisely how they are: they aren't on PCI,
exactly, they're on a broken-bus-interface-"bus" behind the PCI (from
the CPU's perspective) that enforces restrictions that PCI doesn't have.

Thor