Am Dienstag, 22. Mai 2007 17:23 schrieb Alan Stern:
> On Tue, 22 May 2007, Laurent Pinchart wrote:
>
> > The usb_buffer_alloc name is misleading. Many USB driver developers believe
> > it
> > is a generic purpose buffer allocator.
> >
> > I'd like to change usb_buffer_alloc to make it a general purpose allocator.
> > A
> > parameter would tell the function to just allocate memory (default
> > behaviour)
> > or to allocate a DMA coherent mapping as well. We could even pass the URB
> > pointer to the function to set the URB_TRANSFER_NO_DMA_MAP automatically
> > (although usb_buffer_alloc can be used to allocate the setup buffer, so the
> > API might have to be a little different).
>
> It would be simpler and less objectionable to just change the name of
> the routine. If it were called usb_alloc_coherent_DMA_buffer() then
> people wouldn't be tempted to think it was a general-purpose allocator.
I thought a bit about this. Maybe there _is_ room for an allocator that
will provide memory the HCD can get at, but without the full overhead
of allocating a coherent buffer.
Regards
Oliver
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