svn commit: r188350 - in head/sys: amd64/amd64 arm/arm dev/usb2/core i386/i386 ia64/ia64 sys

[Marcel Moolenaar]

On Feb 8, 2009, at 2:54 PM, Warner Losh wrote:

> Author: imp
> Date: Sun Feb  8 22:54:58 2009
> New Revision: 188350
> URL: http://svn.freebsd.org/changeset/base/188350
>
> Log:
>  When bouncing pages, allow a new option to preserve the intra-page
>  offset.  This is needed for the ehci hardware buffer rings that  
> assume
>  this behavior.

I thought we ended up with always doing that?

Bounce buffers may or may not be used, so if the page offset
must be zero for bounce buffers, they must be zero for the
original DMA request. I see no value in re-aligning the DMA
request to a page boundary when bounce buffers are used, but
it is required in some cases to not realign. Hence, why not
always (and unconditionally) preserve the alignment?

-- 
Marcel Moolenaar
xcllnt at mac.com