On Wed, Jun 6, 2012 at 10:26 AM, Xiaofan Chen <[email protected]> wrote: > On Wed, Jun 6, 2012 at 3:32 AM, Sarah Sharp > <[email protected]> wrote: >> On Tue, Jun 05, 2012 at 01:12:44PM -0400, Alan Stern wrote: >>> On Tue, 5 Jun 2012, Sarah Sharp wrote: >>> >>> > Or just change libusb to not break up large transfers, and get rid of >>> > the BULK_CONTINUATION flag all together. libusb should submit >>> > the whole transfer to usbfs with an iovec. usbfs can then: >>> > >>> > a) verify each iovec entry is not too long >>> > b) verify the total length of the iovec isn't too big >>> > c) translate each iovec entry into one sglist vector >>> > d) submit one URB with a populated sglist to the USB core >>> >>> I think this would work. But it wouldn't help people trying to use >>> libusb with xHCI on older kernels. >> >> No, it wouldn't help them. At some point though, users just need to >> upgrade their kernels. And if enterprise distro kernels decide they >> care about those particular users, they can pick up the patches. I >> think Hans was already volunteering to try and push the necessary kernel >> changes for RHEL. > > I think this is fair. xHCI on older kernels may not work well > anyway. BTW, It is similar under Windows that xHCI may or > may not work well on Windows XP/Vista/7 where there is no > official Microsoft driver for them. > > On the other hand, libusb/libusbx should probably need > to put a note that it may not work with USB 3.0 ports prior to kernel > 3.x (where 3.x is the first kernel to solve this issue).
Or if there will no kernel changes due to the complexity required, then we need to put a note that prior to libusb-1.0.10 / libusbx-1.0.13 (if that is the first version to follow Sarah's change), libusb/libusbx may not work with USB 3.0 ports. >> It might be worth it to ensure that the old usbfs calls without iovecs >> can co-exist with the new calls, so that we don't break older API. That >> will make it easier to convince distro kernels to pick up the usbfs >> changes. -- Xiaofan ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ libusbx-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/libusbx-devel
