Date: Sun, 08 Feb 2009 15:01:21 -0800 From: Marcel Moolenaar <xcllnt@mac.com> To: Warner Losh <imp@FreeBSD.org> Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r188350 - in head/sys: amd64/amd64 arm/arm dev/usb2/core i386/i386 ia64/ia64 sys Message-ID: <9E40268E-A2E2-4CAA-AAFE-EB2491175CEE@mac.com> In-Reply-To: <200902082254.n18MsxVt037307@svn.freebsd.org> References: <200902082254.n18MsxVt037307@svn.freebsd.org>
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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@mac.com
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