Revert r266481. It was based on faulty analysis of the problem. A correct

fix is forthcoming.

Obtained from:	Netflix, Inc.

1 files changed, 2 insertions, 25 deletions

diff --git a/sys/x86/x86/busdma_bounce.c b/sys/x86/x86/busdma_bounce.c
index 18e0b75..a767bff 100644
--- a/sys/x86/x86/busdma_bounce.c
+++ b/sys/x86/x86/busdma_bounce.c
@@ -172,35 +172,12 @@ bounce_bus_dma_tag_create(bus_dma_tag_t parent, bus_size_t alignment,
 	newtag->map_count = 0;
 	newtag->segments = NULL;
 
-	/*
-	 * Bouncing might be needed if there's a filter.
-	 * XXX Filters are likely broken as there's no way to
-	 *     guarantee that bounce pages will also satisfy the
-	 *     filter requirement.
-	 */
 	if (parent != NULL && ((newtag->common.filter != NULL) ||
 	    ((parent->common.flags & BUS_DMA_COULD_BOUNCE) != 0)))
 		newtag->common.flags |= BUS_DMA_COULD_BOUNCE;
 
-	/*
-	 * Bouncing might be needed if there's an upper memory
-	 * restriction.
-	 */
-	if (newtag->common.lowaddr < ptoa((vm_paddr_t)Maxmem))
-		newtag->common.flags |= BUS_DMA_COULD_BOUNCE;
-
-	/*
-	 * Bouncing might be needed if there's an alignment
-	 * restriction that can't be satisfied by breaking up
-	 * the segment.
-	 * XXX Need to consider non-natural alignment.
-	 * XXX Static allocations that tie to bus_dmamem_alloc()
-	 *     will likely pass this test and be penalized with
-	 *     the COULD_BOUNCE flag.  Should probably have
-	 *     bus_dmamem_alloc() clear this flag.
-	 */
-	if ((newtag->common.nsegments <= 1) &&
-	    (newtag->common.alignment > 1))
+	if (newtag->common.lowaddr < ptoa((vm_paddr_t)Maxmem) ||
+	    newtag->common.alignment > 1)
 		newtag->common.flags |= BUS_DMA_COULD_BOUNCE;
 
 	if (((newtag->common.flags & BUS_DMA_COULD_BOUNCE) != 0) &&