with IOMMUs and such. There is one usage of the forbidden vtophys()
left in drm_scatter.c which will be fixed up soon. This required a KPI
change for drm_pci_alloc/free() to return/use a drm_dma_handle_t that
keeps track of os-specific bits, rather than just passing around the
vaddr/busaddr/size.
Submitted by: Tonnerre Lombard (partially) Tested on: FreeBSD: Rage128
AGP/PCI Linux: Savage4 AGP/PCI
ioctls with dev_lock, which is a major step toward being able to remove
Giant. Covers some new pieces (dev->unique*) in the core, and avoids
one call down into system internals with the drm lock held, which is
usually bad (FreeBSD LOR #23, #27).