On Thursday 03 February 2011 11:24:23 Daniel O'Connor wrote: > On 03/02/2011, at 17:52, Hans Petter Selasky wrote: > >> I am trying to get it working at the moment, however I'm only finding it > >> capable of 4 or 8 Mb/sec (512 or 1024 byte EP), although perhaps I don't > >> understand how to do ISO transfer properly. > > > > Hi, > > > > You need to set the multiplier to 2 or 3. Then you get 3*1024 bytes at > > maximum. > > OK, so I need.. > usb_xf[i].xf = libusb_alloc_transfer(3); > p = malloc(3 * 1024); > libusb_fill_iso_transfer(usb_xf[i].xf, h, 0x82 p, 3 * 1024, 3, usbcb, > &usb_xf[i], 2000); >
No. Please read the description of wMaxPacketSize in the USB2.0 spec, and the multiplier bits. High-speed USB executes 8 isoc packets per second! Number of packets should not be less than 56 for High-speed USB due to underflow risc. usb_xf[i].xf = libusb_alloc_transfer(56); p = malloc(3 * 1024 * 56); libusb_fill_iso_transfer(usb_xf[i].xf, 0x82, p, 3 * 56 * 1024, 56, usbcb, &usb_xf[i], 2000); libusb_set_iso_packet_lengths(usb_xf[i].xf, 3 * 1024); You need to allocate 2x "libusb_alloc_transfer(56)" and submit to get double buffering! --HPS _______________________________________________ freebsd-usb@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-usb To unsubscribe, send any mail to "freebsd-usb-unsubscr...@freebsd.org"
