blog/data/2014-10-17-debian-firmware-install.txt

   1 Title: Debian Jessie, PXE and automatic firmware installation
   2 Tags: english, debian, isenkram, sysadmin
   3 Date: 2014-10-17 14:10
   4
   5 <p>When PXE installing laptops with Debian, I often run into the
   6 problem that the WiFi card require some firmware to work properly.
   7 And it has been a pain to fix this using preseeding in Debian.
   8 Normally something more is needed.  But thanks to
   9 <a href="https://packages.qa.debian.org/i/isenkram.html">my isenkram
  10 package</a> and its recent tasksel extension, it has now become easy
  11 to do this using simple preseeding.</p>
  12
  13 <p>The isenkram-cli package provide tasksel tasks which will install
  14 firmware for the hardware found in the machine (actually, requested by
  15 the kernel modules for the hardware).  (It can also install user space
  16 programs supporting the hardware detected, but that is not the focus
  17 of this story.)</p>
  18
  19 <p>To get this working in the default installation, two preeseding
  20 values are needed.  First, the isenkram-cli package must be installed
  21 into the target chroot (aka the hard drive) before tasksel is executed
  22 in the pkgsel step of the debian-installer system.  This is done by
  23 preseeding the base-installer/includes debconf value to include the
  24 isenkram-cli package.  The package name is next passed to debootstrap
  25 for installation.  With the isenkram-cli package in place, tasksel
  26 will automatically use the isenkram tasks to detect hardware specific
  27 packages for the machine being installed and install them, because
  28 isenkram-cli contain tasksel tasks.</p>
  29
  30 <p>Second, one need to enable the non-free APT repository, because
  31 most firmware unfortunately is non-free.  This is done by preseeding
  32 the apt-mirror-setup step.  This is unfortunate, but for a lot of
  33 hardware it is the only option in Debian.</p>
  34
  35 <p>The end result is two lines needed in your preseeding file to get
  36 firmware installed automatically by the installer:</p>
  37
  38 <p><blockquote><pre>
  39 base-installer base-installer/includes string isenkram-cli
  40 apt-mirror-setup apt-setup/non-free boolean true
  41 </pre></blockquote></p>
  42
  43 <p>The current version of isenkram-cli in testing/jessie will install
  44 both firmware and user space packages when using this method.  It also
  45 do not work well, so use version 0.15 or later.  Installing both
  46 firmware and user space packages might give you a bit more than you
  47 want, so I decided to split the tasksel task in two, one for firmware
  48 and one for user space programs.  The firmware task is enabled by
  49 default, while the one for user space programs is not.  This split is
  50 implemented in the package currently in unstable.</p>
  51
  52 <p>If you decide to give this a go, please let me know (via email) how
  53 this recipe work for you. :)</p>
  54
  55 <p>So, I bet you are wondering, how can this work.  First and
  56 foremost, it work because tasksel is modular, and driven by whatever
  57 files it find in /usr/lib/tasksel/ and /usr/share/tasksel/.  So the
  58 isenkram-cli package place two files for tasksel to find.  First there
  59 is the task description file (/usr/share/tasksel/descs/isenkram.desc):</p>
  60
  61 <p><blockquote><pre>
  62 Task: isenkram-packages
  63 Section: hardware
  64 Description: Hardware specific packages (autodetected by isenkram)
  65  Based on the detected hardware various hardware specific packages are
  66  proposed.
  67 Test-new-install: show show
  68 Relevance: 8
  69 Packages: for-current-hardware
  70
  71 Task: isenkram-firmware
  72 Section: hardware
  73 Description: Hardware specific firmware packages (autodetected by isenkram)
  74  Based on the detected hardware various hardware specific firmware
  75  packages are proposed.
  76 Test-new-install: mark show
  77 Relevance: 8
  78 Packages: for-current-hardware-firmware
  79 </pre></blockquote></p>
  80
  81 <p>The key parts are Test-new-install which indicate how the task
  82 should be handled and the Packages line referencing to a script in
  83 /usr/lib/tasksel/packages/.  The scripts use other scripts to get a
  84 list of packages to install.  The for-current-hardware-firmware script
  85 look like this to list relevant firmware for the machine:
  86
  87 <p><blockquote><pre>
  88 #!/bin/sh
  89 #
  90 PATH=/usr/sbin:$PATH
  91 export PATH
  92 isenkram-autoinstall-firmware -l
  93 </pre></blockquote></p>
  94
  95 <p>With those two pieces in place, the firmware is installed by
  96 tasksel during the normal d-i run. :)</p>
  97
  98 <p>If you want to test what tasksel will install when isenkram-cli is
  99 installed, run <tt>DEBIAN_PRIORITY=critical tasksel --test
 100 --new-install</tt> to get the list of packages that tasksel would
 101 install.</p>
 102
 103 <p><a href="https://wiki.debian.org/DebianEdu/">Debian Edu</a> will be
 104 pilots in testing this feature, as isenkram is used there now to
 105 install firmware, replacing the earlier scripts.</p>