Let's see if we can get root in general to fail to open this. First paste the following into 'open.c' (without the '========' lines), and then compile that using 'make open'.
=============================================================== #include <stdio.h> #include <stdlib.h> #include <sys/types.h> #include <sys/stat.h> #include <fcntl.h> int main(int argc, char *argv[]) { int ret; if (argc < 2) { printf("try %s /dev/bus/usb/001/013\n", argv[0]); exit(1); } ret = open(argv[1], O_RDWR|O_NONBLOCK); printf("open returned %d\n", ret); close(ret); } =============================================================== Plug in the printer and try starting the VM with libvirt. Look in the log file to get the pathname it is trying to use. Then run open with that file as argument. For instance if you see /dev/bus/usb/001/004: Operation not permitted then try sudo ./open /dev/bus/usb/001/004 If it says it returned a positive number, then it succeeded in opening it. If it returned -1, then we know that in fact root can't open that device, and it isn't just libvirt. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/787091 Title: Unable to use USB device in KVM quest To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/qemu-kvm/+bug/787091/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs