Subject: Re: Valid use of bus_dma(9)?
To: None <>
From: David Young <>
List: tech-kern
Date: 07/23/2004 15:38:09
On Fri, Jul 23, 2004 at 05:19:23PM +0200, Manuel Bouyer wrote:
> bus_dmamem_alloc(9) says:
>             The mapping of this memory is machine-dependent (or "opaque");
> 	    machine-independent code is not to assume that the addresses
> 	    returned are valid in kernel virtual address space, or that the
> 	    addresses returned are system physical addresses.  The address
> To me, this means that we can't make any assumptions about the values returned
> by bus_dmamem_alloc(), and especially it's wrong to assume we can do
> memory-related operations on ds_addr/ds_len.

Network drivers don't copy ds_addr into transmit/receive descriptors?
How does this work if they are not "system physical addresses" ?


David Young             OJC Technologies      Urbana, IL * (217) 278-3933