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

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fix is forthcoming.

Obtained from:	Netflix, Inc.
This commit is contained in:
Scott Long 2014-05-27 14:06:23 +00:00
parent aa475e141c
commit 9359d2ac62
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=266745
1 changed files with 2 additions and 25 deletions
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27
sys/x86/x86/busdma_bounce.c
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@ -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) &&