On Wed, Jan 02 2002, David Brownell wrote:
> > > requirement for drivers is that the transfer buffers can be passed to
> > > pci_map_single() calls by the Host Controller Drivers (HCDs). The
> > > device drivers, and URBs, don't expose such mappings, they only
> > > require that they can be created/destroyed.
> >
> > .. which is the requirement that you want to change to use pci_map_page
> > or pci_map_sg
>
> OK, I think I'm clear on this much then: in 2.5, to support block drivers
> over USB (usb-storage only, for now) there needs to be an addition to
> the buffer addressing model in usbcore, as exposed by URBs.
>
> - Current "transfer_buffer" + "transfer_buffer_length" mode needs to
> stay, since most drivers aren't block drivers.
Why? Surely USB block drivers are not the only ones that want to support
highmem.
> - Add some kind of "page + offset" addressing model.
Yes
> Discussion of details can be taken off LKML, it'd seem. Though I'm
> curious when the scatterlist->address field will vanish, making these
> changes a requirement. Is that a 2.5.2 thing?
Maybe 2.5.3, dunno for sure.
> Also, I noticed that include/asm-sparc/pci.h doesn't include the
> standard pci_map_page() call ... what's up with that? That surely
> causes portability problems.
It probably isn't up to snuff yet.
-- Jens Axboe- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
This archive was generated by hypermail 2b29 : Mon Jan 07 2002 - 21:00:17 EST