Hmm, I just found out that my change to libusb is incompatible with kernel versions < 3.3 How exactly Hans de Geode is going to proceed with this issue? I think I saw a couple of emails about this, but I couldn't find the whole thread.
> On Tue, 26 Jun 2012 11:47:57 +0400 > Igor Kuzmin <para...@ximea.com> wrote: > > > On Mon, 25 Jun 2012 13:26:45 -0700 > > Sarah Sharp <sarah.a.sh...@linux.intel.com> wrote: > > > > > On Fri, Jun 22, 2012 at 03:36:53PM +0400, Igor Kuzmin wrote: > > > > Hello! > > > > > > > > I'm software engineer at XIMEA (www.ximea.com) responsible for Linux > > > > support for our products. We're using libusb-1.0 to handle our USB > > > > cameras, everything works very stable with USB2 controllers, not so > > > > good with XHCI (both with USB2 and USB3 devices). > > > > > > Does your libusb driver submit very large transfers? We ran into an > > > issue with libusb making assumptions about the short packet behavior > > > that just isn't true under xHCI. > > > > > > libusb breaks large transfers into smaller buffers because older kernels > > > had a limit on how large each buffer could be. Newer kernels now have a > > > limit on the total size of all mapped usbfs buffers. So libusb would > > > break larger transfers into a couple of usbfs URB submissions, and usbfs > > > would assume that a short packet would stop the queue long enough for it > > > to cancel any URBs that were part of that transfer. But that's not true > > > under xHCI, so your application would see a short transfer completion > > > followed by a canceled URB completion. > > > > > > Basically, libusb just needs to be fixed to not break transfers into > > > smaller chunks. Hans de Geode volunteered to work on this. > > > > Yes, I stumbled into this issue, for the time being we patched libusb, > > so that MAX_BULK_BUFFER_LENGTH is 1MB (that's exactly how big is the > > transfers we submit, so no splitting). Without this change it just > > doesn't work at all (there are some short transfers). Good to hear that > > somebody is working on it, I submitted my patch to libusb's trac, but > > had no response yet. ------------------------------------------------------------------------------ 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 libusbx-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/libusbx-devel
