Re: [spi-devel-general] Re: SPI

[David B. <da...@pa...>]

On Wednesday 30 November 2005 12:25 am, Vitaly Wool wrote:
> 
> Moreover, I've got a strong suspicion that spi_write_then_read may not 
> work with DMA in some cases when compiled as a module.

I _know_ otherwise.  By definition, memory from kmalloc() may be used
with DMA.  I'm still rather puzzled about why you keep making strange
statements about DMA ... ones contrary to how Linux works.  Please
review the relevant parts of Documentation/DMA-mapping.txt soon, like
this one:

	If you acquired your memory via the page allocator
	(i.e. __get_free_page*()) or the generic memory allocators
	(i.e. kmalloc() or kmem_cache_alloc()) then you may DMA to/from
	that memory using the addresses returned from those routines.

That seems rather conclusive doesn't it?  I've pointed that out to
you on more than one occasion...

- Dave