On Sun, 30 Jan 2005, Alan Stern wrote: > On Sun, 30 Jan 2005, Antonio Vinci wrote: > > > Hi all, > > I'm new in this list and i'm approaching libusb programming. > > Trying to write a sane backend for my scanner, i do the following steps: > > > > open the device with scanner = usb_open(dev); > > set the device configuration with usb_set_configuration(scanner, 1); > > claim the device with usb_claim_interface(scanner, 0); > > > > when i try to send any data to the device: > > usb_bulk_write(scanner, 81, cmd, length, 1000) > > returns -22 (Invalid argument). > > > > I'm wondering what is the "Invalid argument" referred to? > > Should the 81 really be 0x81?
No, obviously it shouldn't since 0x81 would be in IN endpoint and this is a write. There are several things that can result in -EINVAL. Among them are: using a non-existent endpoint, trying to transfer too much data, passing an invalid pointer for the buffer address, and passing a negative transfer length. The last three seem unlikely in your case, but maybe the endpoint number is wrong. Have you looked in /proc/bus/usb/devices to check? Alan Stern ------------------------------------------------------- This SF.Net email is sponsored by: IntelliVIEW -- Interactive Reporting Tool for open source databases. Create drag-&-drop reports. Save time by over 75%! Publish reports on the web. Export to DOC, XLS, RTF, etc. Download a FREE copy at http://www.intelliview.com/go/osdn_nl _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
