Apply by doing:
	cd /usr/src
	patch -p0 < 003_bus_dma.patch

Then build and install a new kernel.

Index: sys/arch/i386/i386/bus_dma.c
===================================================================
RCS file: /cvs/src/sys/arch/i386/i386/bus_dma.c,v
retrieving revision 1.3
diff -u -p sys/arch/i386/i386/bus_dma.c
--- sys/arch/i386/i386/bus_dma.c	5 Feb 2009 01:13:21 -0000	1.3
+++ sys/arch/i386/i386/bus_dma.c	24 Apr 2009 13:54:31 -0000
@@ -370,6 +370,7 @@ _bus_dmamem_map(bus_dma_tag_t t, bus_dma_segment_t *se
 	bus_addr_t addr;
 	int curseg, pmapflags;
 
+	pmapflags = VM_PROT_READ | VM_PROT_WRITE | PMAP_WIRED;
 	if (flags & BUS_DMA_NOCACHE)
 		pmapflags |= PMAP_NOCACHE;
 
@@ -387,9 +388,7 @@ _bus_dmamem_map(bus_dma_tag_t t, bus_dma_segment_t *se
 			if (size == 0)
 				panic("_bus_dmamem_map: size botch");
 			pmap_enter(pmap_kernel(), va, addr,
-			    VM_PROT_READ | VM_PROT_WRITE,
-			    VM_PROT_READ | VM_PROT_WRITE | PMAP_WIRED |
-			    pmapflags);
+			    VM_PROT_READ | VM_PROT_WRITE, pmapflags);
 		}
 	}
 	pmap_update(pmap_kernel());