I was trying to use QEMU with USB in Ubuntu 7.10 Gutsy when I found this bug. I comment out the magic lines in /etc/init.d/mountdevsubfs.sh, started it, but still couldn't use USB in QEMU. Everything inside /proc/bus/usb/ and /dev/bus/usb was owned by root and QEMU couldn't read/write in it. I searched the web for something to change /dev/bus/usb/ and /proc/bus/usb/ permissions. QEMU docs says to "chown -R" all /proc/bus/usb/ and this was a problem since it "doesn't exist".
I found this: http://www.ubuntu1501.com/2007/12/installing-virtualbox- with-usb-support.html and adapted it to QEMU. Basicaly, I added a new system group called "usbusers", added my username to that new system group and added a line in /etc/fstab setting the GID of /proc/bus/usb. I didn't need to change /etc/udev/rules.d/40-permissions.rules! All the process: # Edit, uncomment "magic" and start the file /etc/init.d/mountdevsubfs.sh # Create a system group for usb users: sudo addgroup --system usbusers # Output was GID 128 # Add user to usbusers group: sudo adduser $USER usbusers # With the lines in /etc/init.d/mountdevsubfs.sh comment out, # edit /etc/fstab: sudo nano /etc/fstab # Add the following line: # 128 is the GID of the group "usbusers". none /proc/bus/usb usbfs devgid=128,devmode=664 0 0 # Reboot. After restarting the group owner of the devices were "usbusers": $ ls -la /proc/bus/usb/ total 0 drwxr-xr-x 7 root root 0 2008-03-11 14:45 . dr-xr-xr-x 5 root root 0 2008-03-11 14:46 .. dr-xr-xr-x 2 root root 0 2008-03-11 14:45 001 dr-xr-xr-x 2 root root 0 2008-03-11 14:45 002 dr-xr-xr-x 2 root root 0 2008-03-11 14:45 003 dr-xr-xr-x 2 root root 0 2008-03-11 14:45 004 dr-xr-xr-x 2 root root 0 2008-03-11 14:45 005 -r--r--r-- 1 root root 0 2008-03-11 14:45 devices $ ls -la /proc/bus/usb/003 total 0 dr-xr-xr-x 2 root root 0 2008-03-11 14:45 . drwxr-xr-x 7 root root 0 2008-03-11 14:45 .. -rw-rw-r-- 1 root usbusers 43 2008-03-11 14:45 001 # Eject the USB device in Gnome before using QEMU! # Run QEMU with the option "-usb" or "-usbdevice host:1234:5678". This was the way I got this working 100%. -- Could not open /proc/bus/usb/devices https://bugs.launchpad.net/bugs/156085 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs