# Reference: Features

'Features' provide a mechanism for working out which packages should be included in the generated images. Distributions can select which features they want to support through the DISTRO_FEATURES variable which is set in the distribution configuration file (poky.conf for Poky). Machine features are set in the MACHINE_FEATURES variable which is set in the machine configuration file and specifies which hardware features a given machine has.

These two variables are combined to work out which kernel modules, utilities and other packages to include. A given distribution can support a selected subset of features so some machine features might not be included if the distribution itself doesn't support them.

## Distro

The items below are valid options for DISTRO_FEATURES.

- alsa - ALSA support will be included (OSS compatibility kernel modules will be installed if available)

- bluetooth - Include bluetooth support (integrated BT only)

- ext2 - Include tools for supporting for devices with internal HDD/Microdrive for storing files (instead of Flash only devices)

- irda - Include Irda support

- keyboard - Include keyboard support (e.g. keymaps will be loaded during boot).

- pci - Include PCI bus support

- pcmcia - Include PCMCIA/CompactFlash support

- usbgadget - USB Gadget Device support (for USB networking/serial/storage)

- usbhost - USB Host support (allows to connect external keyboard, mouse, storage, network etc)

- wifi - WiFi support (integrated only)

- cramfs - CramFS support

- ipsec - IPSec support

- ipv6 - IPv6 support

- nfs - NFS client support (for mounting NFS exports on device)

- ppp - PPP dialup support

- smbfs - SMB networks client support (for mounting Samba/Microsoft Windows shares on device)

## Machine

The items below are valid options for MACHINE_FEATURES.

- acpi - Hardware has ACPI (x86/x86_64 only)

- alsa - Hardware has ALSA audio drivers

- apm - Hardware uses APM (or APM emulation)

- bluetooth - Hardware has integrated BT

- ext2 - Hardware HDD or Microdrive

- irda - Hardware has Irda support

- keyboard - Hardware has a keyboard

- pci - Hardware has a PCI bus

- pcmcia - Hardware has PCMCIA or CompactFlash sockets

- screen - Hardware has a screen

- serial - Hardware has serial support (usually RS232)

- touchscreen - Hardware has a touchscreen

- usbgadget - Hardware is USB gadget device capable

- usbhost - Hardware is USB Host capable

- wifi - Hardware has integrated WiFi

## Reference: Images

The contents of images generated by Poky can be controlled by the IMAGE_FEATURES variable in local.conf. Through this you can add several different predefined packages such as development utilities or packages with debug information needed to investigate application problems or profile applications.

Current list of IMAGE_FEATURES contains:

- apps-console-core - Core console applications such as ssh daemon, avahi daemon, portmap (for mounting NFS shares)

- x11-base - X11 server + minimal desktop

- x11-sato - OpenedHand Sato environment

- apps-x11-core - Core X11 applications such as an X Terminal, file manager, file editor

- apps-x11-games - A set of X11 games

- apps-x11-pimlico - OpenedHand Pimlico application suite

- tools-sdk - A full SDK which runs on device

- tools-debug - Debugging tools such as strace and gdb

- tools-profile - Profiling tools such as oprofile, exmap and LTTng

- tools-testapps - Device testing tools (e.g. touchscreen debugging)

- nfs-server - NFS server (exports / over NFS to everybody)

- dev-pkgs - Development packages (headers and extra library links) for all packages installed in a given image

- dbg-pkgs - Debug packages for all packages installed in a given image