ubuntu-drivers-common

This package aggregates and abstracts Ubuntu specific logic and knowledge about third-party driver packages, and provides APIs for installers and driver configuration GUIs. It also contains some NVidia specific support code to find the most appropriate driver version (as we usually ship several), as well as setting up the alternatives symlinks that the proprietary NVidia and FGLRX packages use.

Command line interface

The simplest frontend is the ubuntu-drivers command line tool. You can use it to show the available driver packages which apply to the current system (ubuntu-drivers list), or to install all drivers which are appropriate for automatic installation (sudo ubuntu-drivers autoinstall), which is mostly useful for integration into installers.

Please see ubuntu-drivers --help for details.

Python API

The UbuntuDrivers.detect Python module provides some functions to detect the system's hardware, matching driver packages, and packages which are eligible for automatic installation.

The three main functions are:

1. Which driver packages apply to this system?

   packages = UbuntuDrivers.detect.system_driver_packages()

2. Which devices need drivers, and which packages do they need?

   driver_info = UbuntuDrivers.detect.system_device_drivers()

3. Which driver package(s) applies to this piece of hardware?

   import apt
   apt_cache = apt.Cache
   apt_packages = UbuntuDrivers.detect.packages_for_modalias(apt_cache, modalias)

These functions only use python-apt. They do not need any other dependencies, root privileges, D-BUS calls, etc.

Detection logic

The principal method of mapping hardware to driver packages is to use modalias patterns. Hardware devices export a "modalias" sysfs attribute, for example

$ cat /sys/devices/pci0000:00/0000:00:1b.0/modalias
pci:v00008086d00003B56sv000017AAsd0000215Ebc04sc03i00

Kernel modules declare which hardware they can handle with modalias patterns (globs), e. g.:

$ modinfo snd_hda_intel
[...]
alias:          pci:v00008086d*sv*sd*bc04sc03i00*

Driver packages which are not installed by default (e. g. backports of drivers from newer Linux packages, or the proprietary NVidia driver package nvidia-current) have a Modaliases: package header which includes all modalias patterns from all kernel modules that they ship. It is recommended to add these headers to the package with dh_modaliases(1).

ubuntu-drivers-common uses these package headers to map a particular piece of hardware (identified by a modalias) to the driver packages which cover that hardware.

Custom detection plugins

For some kinds of drivers the modalias detection approach does not work. For example, the "sl-modem-daemon" driver requires some checks in /proc/asound/cards and aplay -l to decide whether or not it applies to the system. These special cases can be put into a detection plugin, by adding a small piece of Python code to /usr/share/ubuntu-drivers-common/detect/NAME.py (shipped in ./detect-plugins/ in the ubuntu-drivers-common source). They need to export a method

   def detect(apt_cache):
      # do detection logic here
      return ['driver_package', ...]

which can do any kind of detection and then return the resulting set of packages that apply to the current system. Please note that this cannot rely on having root privileges.

Autopkgtest

For the autopkgtest of ubuntu-drivers, a useful command can be used when developing test cases:

$ PYTHONPATH=. tests/run test_ubuntu_drivers

Once the new test case is completed but the others failed, suggest to use a clean environment to verify, such as: pbuilder, sbuild or dput it to PPA to build.