Subject: Re: FreeBSD Bus DMA (was Re: AdvanSys board support)
To: Noriyuki Soda <email@example.com>
From: Jason Thorpe <firstname.lastname@example.org>
Date: 06/11/1998 15:52:04
On Fri, 12 Jun 1998 06:08:39 +0900 (JST)
Noriyuki Soda <email@example.com> wrote:
> About bus_dmamap_callback_t, I think that reducing bounce memory size
> is certainly good thing. But it is pain if we must use callback in all
> cases. (Think about hardware_scb in ahc driver.)
> I think NetBSD's interface is more convenient than FreeBSD's.
> Isn't there other way to reduce bounce memory ?
Yes, lots of ways. But you don't have to change the interface to
bus_dma to do it. The bounce buffer size issue is largely an issue
of the implementation that drivers never see. To be quite honest,
I implemented it the way I did because bounce buffers were SORELY
needed, and didn't have the time to implement them differently underneath.
I've actually improved the implementation of bounce buffers a little since
the original implementation.
Jason R. Thorpe firstname.lastname@example.org
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