Sun Microsystems 3.0.0 user manual VBoxSVC IPC issues, USB not working

11 Troubleshooting

for IDE CD/DVD writer units this must refer to the appropriate SCSI CD-ROM device node (e.g. /dev/scd0) if the ide-scsi kernel module is loaded. This module is required for CD/DVD writer support with all Linux 2.4 kernels and some early 2.6 kernels. Many Linux distributions load this module whenever a CD/DVD writer is detected in the system, even if the kernel would support CD/DVD writers without the module. VirtualBox supports the use of IDE device files (e.g. /dev/hdc), provided the kernel supports this and the ide-scsi module is not loaded.

Similar rules (except that within the guest the CD/DVD writer is always an IDE device) apply to the guest configuration. Since this setup is very common, it is likely that the default configuration of the guest works as expected.

11.5.6 VBoxSVC IPC issues

On Linux, VirtualBox makes use of a custom version of Mozilla XPCOM (cross plat- form component object model) for inter- and intra-process communication (IPC). The process VBoxSVC serves as a communication hub between different VirtualBox pro- cesses and maintains the global configuration, i.e. the XML database. When starting a VirtualBox component, the processes VBoxSVC and VirtualBoxXPCOMIPCD are started automatically. They are only accessible from the user account they are running under. VBoxSVC owns the VirtualBox configuration database which normally resides

in ˜. While it is running, the configuration files are locked. Com- /.VirtualBox

munication between the various VirtualBox components and VBoxSVC is performed through a local domain socket residing in /tmp/.vbox-<username>-ipc. In case there are communication problems (i.e. a VirtualBox application cannot communicate with VBoxSVC), terminate the daemons and remove the local domain socket directory.

11.5.7 USB not working

If USB is not working on your Linux host, make sure that the current user is a mem- ber of the vboxusers group. On older hosts, you need to make sure that the user has permission to access the USB filesystem (usbfs), which VirtualBox relies on to retrieve valid information about your host’s USB devices. The rest of this section only applies to those older systems.

Note: The current rdesktop-vrdp implementation does not support accessing USB devices through the sysfs!

As usbfs is a virtual filesystem, a chmod on /proc/bus/usb has no effect. The permissions for usbfs can therefore only be changed by editing the /etc/fstab file.

For example, most Linux distributions have a user group called usb or similar, of which the current user must be a member. To give all users of that group access to usbfs, make sure the following line is present:

# 85 is the USB group

none /proc/bus/usb usbfs devgid=85,devmode=664 0 0

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