Messages in this thread | | | Date | Mon, 22 Sep 2008 22:35:18 +0200 | From | Andi Kleen <> | Subject | Re: [PATCH 0/3] fix GART to respect device's dma_mask about virtual mappings |
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On Tue, Sep 23, 2008 at 04:12:33AM +0900, FUJITA Tomonori wrote: > Sure, pci-nommu's map_sg/map_single doesn't handle it. But we handle > this issue somewhere else (like b44 keeps own DMA buffer)?
Yes, b44 handles it on its own. It has to for 32bit which always has a nop map_sg/single. Also some other subsystems like the block layer do it implicitely.
> 1. not all map_sg/map_single (e.g. pci-nommu) can't handle it.
and especially i386
> 2. we already have workarounds for it somewhere else so > map_sg/map_single don't need to handle it. > 3. I changed GART map_sg/map_signle to handle it. I thought if it > can handle it, for example, b44 doesn't go the workaround path. It > would be a good thing. > 4. But GART cannot remap to addresses < 4GB reliably, so my above > argument doesn't always work. > 5. Then my patch doesn't break anything but it's almost meaningless.
Correct.
-Andi -- ak@linux.intel.com
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