Index: src/sys/amd64/amd64/busdma_machdep.c
===================================================================
RCS file: /home/ncvs/src/sys/amd64/amd64/busdma_machdep.c,v
retrieving revision 1.79
diff -u -r1.79 busdma_machdep.c
--- src/sys/amd64/amd64/busdma_machdep.c	6 Mar 2007 18:28:42 -0000	1.79
+++ src/sys/amd64/amd64/busdma_machdep.c	18 Mar 2007 17:06:12 -0000
@@ -48,6 +48,7 @@
 #include <machine/atomic.h>
 #include <machine/bus.h>
 #include <machine/md_var.h>
+#include <machine/specialreg.h>
 
 #define MAX_BPAGES 8192
 
@@ -522,6 +523,9 @@
 	} else if ((uintptr_t)*vaddr & (dmat->alignment - 1)) {
 		printf("bus_dmamem_alloc failed to align memory properly.\n");
 	}
+	if (flags & BUS_DMA_NOCACHE)
+		pmap_change_attr((vm_offset_t)*vaddr, dmat->maxsize,
+		    PAT_UNCACHEABLE);
 	CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d",
 	    __func__, dmat, dmat->flags, ENOMEM);
 	return (0);
Index: src/sys/i386/i386/busdma_machdep.c
===================================================================
RCS file: /home/ncvs/src/sys/i386/i386/busdma_machdep.c,v
retrieving revision 1.85
diff -u -r1.85 busdma_machdep.c
--- src/sys/i386/i386/busdma_machdep.c	6 Mar 2007 18:28:42 -0000	1.85
+++ src/sys/i386/i386/busdma_machdep.c	18 Mar 2007 17:06:12 -0000
@@ -51,6 +51,7 @@
 #include <machine/atomic.h>
 #include <machine/bus.h>
 #include <machine/md_var.h>
+#include <machine/specialreg.h>
 
 #define MAX_BPAGES 512
 #define BUS_DMA_COULD_BOUNCE	BUS_DMA_BUS3
@@ -530,6 +531,9 @@
 	} else if ((uintptr_t)*vaddr & (dmat->alignment - 1)) {
 		printf("bus_dmamem_alloc failed to align memory properly.\n");
 	}
+	if (flags & BUS_DMA_NOCACHE)
+		pmap_change_attr((vm_offset_t)*vaddr, dmat->maxsize,
+		    PAT_UNCACHEABLE);
 	CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d",
 	    __func__, dmat, dmat->flags, ENOMEM);
 	return (0);
Index: src/sys/dev/sound/pci/hda/hdac.c
===================================================================
RCS file: /home/ncvs/src/sys/dev/sound/pci/hda/hdac.c,v
retrieving revision 1.30
diff -u -r1.30 hdac.c
--- src/sys/dev/sound/pci/hda/hdac.c	16 Mar 2007 17:18:17 -0000	1.30
+++ src/sys/dev/sound/pci/hda/hdac.c	18 Mar 2007 15:12:20 -0000
@@ -1166,6 +1166,11 @@
  * This function allocate and setup a dma region (struct hdac_dma).
  * It must be freed by a corresponding hdac_dma_free.
  ****************************************************************************/
+
+#ifndef BUS_DMA_NOCACHE
+#define BUS_DMA_NOCACHE	BUS_DMA_COHERENT
+#endif
+
 static int
 hdac_dma_alloc(struct hdac_softc *sc, struct hdac_dma *dma, bus_size_t size)
 {
@@ -1203,7 +1208,8 @@
 	 * Allocate DMA memory
 	 */
 	result = bus_dmamem_alloc(dma->dma_tag, (void **)&dma->dma_vaddr,
-	    BUS_DMA_NOWAIT | BUS_DMA_COHERENT, &dma->dma_map);
+	    BUS_DMA_NOWAIT | BUS_DMA_COHERENT | BUS_DMA_NOCACHE | BUS_DMA_ZERO,
+	    &dma->dma_map);
 	if (result != 0) {
 		device_printf(sc->dev, "%s: bus_dmamem_alloc failed (%x)\n",
 		    __func__, result);
@@ -1221,7 +1227,6 @@
 		    __func__, result);
 		goto fail;
 	}
-	bzero((void *)dma->dma_vaddr, size);
 	hdac_dma_nocache(dma->dma_vaddr);
 
 	return (0);
@@ -2674,7 +2679,9 @@
 		return (NULL);
 	}
 
-	if (sndbuf_alloc(ch->b, sc->chan_dmat, sc->chan_size) != 0)
+	if (sndbuf_dmamem_alloc(ch->b, sc->chan_dmat,
+	    BUS_DMA_NOWAIT | BUS_DMA_COHERENT | BUS_DMA_NOCACHE | BUS_DMA_ZERO,
+	    sc->chan_size) != 0)
 		return (NULL);
 
 	hdac_dma_nocache(ch->b->buf);
Index: src/sys/dev/sound/pcm/buffer.c
===================================================================
RCS file: /home/ncvs/src/sys/dev/sound/pcm/buffer.c,v
retrieving revision 1.32
diff -u -r1.32 buffer.c
--- src/sys/dev/sound/pcm/buffer.c	16 Mar 2007 17:13:44 -0000	1.32
+++ src/sys/dev/sound/pcm/buffer.c	18 Mar 2007 15:12:20 -0000
@@ -83,16 +83,18 @@
  */
 
 int
-sndbuf_alloc(struct snd_dbuf *b, bus_dma_tag_t dmatag, unsigned int size)
+sndbuf_dmamem_alloc(struct snd_dbuf *b, bus_dma_tag_t dmatag, int dmaflags,
+    unsigned int size)
 {
 	int ret;
 
 	b->dmatag = dmatag;
+	b->dmaflags = dmaflags;
 	b->maxsize = size;
 	b->bufsize = b->maxsize;
 	b->buf_addr = 0;
 	b->flags |= SNDBUF_F_MANAGED;
-	if (bus_dmamem_alloc(b->dmatag, (void **)&b->buf, BUS_DMA_NOWAIT,
+	if (bus_dmamem_alloc(b->dmatag, (void **)&b->buf, b->dmaflags,
 	    &b->dmamap))
 		return (ENOMEM);
 	if (bus_dmamap_load(b->dmatag, b->dmamap, b->buf, b->maxsize,
@@ -105,10 +107,17 @@
 	ret = sndbuf_resize(b, 2, b->maxsize / 2);
 	if (ret != 0)
 		sndbuf_free(b);
+
 	return (ret);
 }
 
 int
+sndbuf_alloc(struct snd_dbuf *b, bus_dma_tag_t dmatag, unsigned int size)
+{
+	return (sndbuf_dmamem_alloc(b, dmatag, BUS_DMA_NOWAIT, size));
+}
+
+int
 sndbuf_setup(struct snd_dbuf *b, void *buf, unsigned int size)
 {
 	if (buf)
Index: src/sys/dev/sound/pcm/buffer.h
===================================================================
RCS file: /home/ncvs/src/sys/dev/sound/pcm/buffer.h,v
retrieving revision 1.14
diff -u -r1.14 buffer.h
--- src/sys/dev/sound/pcm/buffer.h	1 Feb 2007 09:46:03 -0000	1.14
+++ src/sys/dev/sound/pcm/buffer.h	18 Mar 2007 15:12:20 -0000
@@ -54,6 +54,7 @@
 	u_int32_t flags;
 	bus_dmamap_t dmamap;
 	bus_dma_tag_t dmatag;
+	int dmaflags;
 	u_int32_t buf_addr;
 	struct selinfo sel;
 	struct pcm_channel *channel;
@@ -65,6 +66,7 @@
 
 void sndbuf_dump(struct snd_dbuf *b, char *s, u_int32_t what);
 
+int sndbuf_dmamem_alloc(struct snd_dbuf *b, bus_dma_tag_t dmatag, int dmaflags, unsigned int size);
 int sndbuf_alloc(struct snd_dbuf *b, bus_dma_tag_t dmatag, unsigned int size);
 int sndbuf_setup(struct snd_dbuf *b, void *buf, unsigned int size);
 void sndbuf_free(struct snd_dbuf *b);