On Wed, Jul 31, 2013 at 7:12 PM, Oliver Neukum <oneu...@suse.de> wrote: > On Wed, 2013-07-31 at 18:51 +0800, Ming Lei wrote: >> Hi, >> >> This patchset allows drivers to pass sg buffers which size can't be divided >> by max packet size of endpoint if the host controllers support this kind >> of sg buffers. > > Cool. One question though. It makes sense to use sg only > if all elements are in memory capable of DMA. It seems to be possible > to have HCs which can do unlimited sg but are limited to 32bit DMA.
For current usbnet devices which supports TSO, one header need to add before skb->data from network stack, so basically the first two elements aren't OK for other HCs(EHCI/UHCI/...) to DMA from SG. Thanks, -- Ming Le -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
