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Date: Tue, 06 Aug 2013 08:59:55 +0200
From: Hans Petter Selasky <hps@bitfrost.no>
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To: "aseem.jolly" <aseem.jolly@gmail.com>
Subject: Re: USB DMA memory Allocation
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On 08/06/13 03:24, aseem.jolly wrote:
> I don't want to play around with 'kern.maxbcache', can we actually allow
> driver to support 64 bit DMA?
> In future we can use a bootarg/sysctl to enable this support if someone
> comes across this issue else we will use 32 bit DMA allocations.
>
> I am willing to enable this support, please guide me.
>

Hi,

You can start with the EHCI driver, if you like. Download the EHCI PDF 
from INTEL's site. Figure out all the 32-bit HIGH fields and put valid 
data in them. For all 32-bit address there is a corresponding 32-bit 
high field.

Thank you!

--HPS