Subject: Re: Question about bus_dma and mbufs
To: Dave Huang <>
From: Jason Thorpe <>
List: tech-net
Date: 07/04/2005 17:16:10
On Jul 4, 2005, at 3:55 PM, Dave Huang wrote:

> Is there a way for me to do this with the various bus_dma(9) and/or
> mbuf(9) routines, or will I have to copy the mbuf chain into my own
> buffer that has the necessary requirements?

There is a way to specify the max segments parameter, but bus_dma  
will not automatically bounce for you... it would simply return  
E2BIG, which would mean your driver would have to handle that.

Take a look at dev/ic/tulip.c, right around line 776 (in -current) to  
see how the tlp driver handles situations like this.

-- thorpej