Hotplug Hardware Configuration

Since version 2.0, T2 Linux includes an automatic hardware detection and configuration system, including configuration of devices plugged into the system at run-time.

Since hotplug++ is exclusively designed around the hotplug mechanism of recent Linux kernels the system recognizes devices in the same way whether they where present during system boot-up or added to a running system. This is a major improvement over other systems where this two use-cases have a different code path and thus leading to inconsistencies.

The functionality of hotplug++ is quite trivial: When a new device is detected, hotplug++ matches its various ID's against the available kernel modules. If a kernel module is found user configurations are checked and the resulting actions are executed. At system startup those hotplug events are synthesized for the hardware already present and thus resulting in exactly the same configuration and behavior whenever the device is added or present in the system.

It is possible to force the load of modules for a given subsystem - or to 'blacklist' certain modules that are either unwanted or known to malfunction.

For some subsystems, for example USB or ieee1394 (also known as Firewire or iLink) the action might include to set the permission of device files for access by user-space application such as SANE and GPhoto.

The list of subsystems includes: pci, isapnp, macio, usb, ieee1394, net and scsi.

Configuration Files

Aside the Linux kernel module map files hotplug++ reads the blacklist from /etc/conf/blacklist which can contain comments prefixed with a hash ('\#') and otherwise contain one module name per line.