crypto PC/SC Architecture smartcard middleware library Use dev-libs/libusb detection to hotplug new smartcard readers. Use dev-libs/libusb detection to hotplug new smartcard readers. This flag only makes sense on non-Linux systems, as on Linux, sys-fs/udev is used instead. Use dev-libs/libusb detection to hotplug new smartcard readers. This flag should only be enabled if you're running a non-Linux kernel or you don't want to use sys-fs/udev. Use sys-fs/udev rules to handle devices' permissions and hotplug support. Unless you know what you're doing do not disable this flag on Linux kernels. This is provided as an option for completeness.