Petter Reinholdtsen

Entries from January 2013.

Welcome to the world, Isenkram!
22nd January 2013

Yesterday, I asked for testers for my prototype for making Debian better at handling pluggable hardware devices, which I set out to create earlier this month. Several valuable testers showed up, and caused me to really want to to open up the development to more people. But before I did this, I want to come up with a sensible name for this project. Today I finally decided on a new name, and I have renamed the project from hw-support-handler to this new name. In the process, I moved the source to git and made it available as a collab-maint repository in Debian. The new name? It is Isenkram. To fetch and build the latest version of the source, use

git clone
cd isenkram && git-buildpackage -us -uc

I have not yet adjusted all files to use the new name yet. If you want to hack on the source or improve the package, please go ahead. But please talk to me first on IRC or via email before you do major changes, to make sure we do not step on each others toes. :)

If you wonder what 'isenkram' is, it is a Norwegian word for iron stuff, typically meaning tools, nails, screws, etc. Typical hardware stuff, in other words. I've been told it is the Norwegian variant of the German word eisenkram, for those that are familiar with that word.

Update 2013-01-26: Added -us -us to build instructions, to avoid confusing people with an error from the signing process.

Update 2013-01-27: Switch to HTTP URL for the git clone argument to avoid the need for authentication.

Tags: debian, english, isenkram.
First prototype ready making hardware easier to use in Debian
21st January 2013

Early this month I set out to try to improve the Debian support for pluggable hardware devices. Now my prototype is working, and it is ready for a larger audience. To test it, fetch the source from the Debian Edu subversion repository, build and install the package. You might have to log out and in again activate the autostart script.

The design is simple:

I still need to come up with a better name for the system. Here are some screen shots showing the prototype in action. First the notification, then the password request, and finally the request to approve all the dependencies. Sorry for the Norwegian Bokmål GUI.

The prototype still need to be improved with longer timeouts, but is already useful. The database of hardware to package mappings also need more work. It is currently compatible with the Ubuntu way of storing such information in the package control file, but could be changed to use other formats instead or in addition to the current method. I've dropped the use of discover for this mapping, as the modalias approach is more flexible and easier to use on Linux as long as the Linux kernel expose its modalias strings directly.

Update 2013-01-21 16:50: Due to popular demand, here is the command required to check out and build the source: Use 'svn checkout svn://; cd hw-support-handler; debuild'. If you lack debuild, install the devscripts package.

Update 2013-01-23 12:00: The project is now renamed to Isenkram and the source moved from the Debian Edu subversion repository to a Debian collab-maint git repository. See build instructions for details.

Tags: debian, english, isenkram.
Thank you Thinkpad X41, for your long and trustworthy service
19th January 2013

This Christmas my trusty old laptop died. It died quietly and suddenly in bed. With a quiet whimper, it went completely quiet and black. The power button was no longer able to turn it on. It was a IBM Thinkpad X41, and the best laptop I ever had. Better than both Thinkpads X30, X31, X40, X60, X61 and X61S. Far better than the Compaq I had before that. Now I need to find a replacement. To keep going during Christmas, I moved the one year old SSD disk to my old X40 where it fitted (only one I had left that could use it), but it is not a durable solution.

My laptop needs are fairly modest. This is my wishlist from when I got a new one more than 10 years ago. It still holds true.:)

You will notice that there are no RAM and CPU requirements in the list. The reason is simply that the specifications on laptops the last 10-15 years have been sufficient for my needs, and I have to look at other features to choose my laptop. But are there still made as robust laptops as my X41? The Thinkpad X60/X61 proved to be less robust, and Thinkpads seem to be heading in the wrong direction since Lenovo took over. But I've been told that X220 and X1 Carbon might still be useful.

Perhaps I should rethink my needs, and look for a pad with an external keyboard? I'll have to check the Linux Laptops site for well-supported laptops, or perhaps just buy one preinstalled from one of the vendors listed on the Linux Pre-loaded site.

Tags: debian, english.
How to find a browser plugin supporting a given MIME type
18th January 2013

Some times I try to figure out which Iceweasel browser plugin to install to get support for a given MIME type. Thanks to specifications done by Ubuntu and Mozilla, it is possible to do this in Debian. Unfortunately, not very many packages provide the needed meta information, Anyway, here is a small script to look up all browser plugin packages announcing ther MIME support using this specification:

import sys
import apt
def pkgs_handling_mimetype(mimetype):
    cache = apt.Cache()
    thepkgs = []
    for pkg in cache:
        version = pkg.candidate
        if version is None:
            version = pkg.installed
        if version is None:
        record = version.record
        if not record.has_key('Npp-MimeType'):
        mime_types = record['Npp-MimeType'].split(',')
        for t in mime_types:
            t = t.rstrip().strip()
            if t == mimetype:
    return thepkgs
mimetype = "audio/ogg"
if 1 < len(sys.argv):
    mimetype = sys.argv[1]
print "Browser plugin packages supporting %s:" % mimetype
for pkg in pkgs_handling_mimetype(mimetype):
    print "  %s" %pkg

It can be used like this to look up a given MIME type:

% ./apt-find-browserplug-for-mimetype 
Browser plugin packages supporting audio/ogg:
% ./apt-find-browserplug-for-mimetype application/x-shockwave-flash
Browser plugin packages supporting application/x-shockwave-flash:

In Ubuntu this mechanism is combined with support in the browser itself to query for plugins and propose to install the needed packages. It would be great if Debian supported such feature too. Is anyone working on adding it?

Update 2013-01-18 14:20: The Debian BTS request for icweasel support for this feature is #484010 from 2008 (and #698426 from today). Lack of manpower and wish for a different design is the reason thus feature is not yet in iceweasel from Debian.

Tags: debian, english.
What is the most supported MIME type in Debian?
16th January 2013

The DEP-11 proposal to add AppStream information to the Debian archive, is a proposal to make it possible for a Desktop application to propose to the user some package to install to gain support for a given MIME type, font, library etc. that is currently missing. With such mechanism in place, it would be possible for the desktop to automatically propose and install leocad if some LDraw file is downloaded by the browser.

To get some idea about the current content of the archive, I decided to write a simple program to extract all .desktop files from the Debian archive and look up the claimed MIME support there. The result can be found on the Skolelinux FTP site. Using the collected information, it become possible to answer the question in the title. Here are the 20 most supported MIME types in Debian stable (Squeeze), testing (Wheezy) and unstable (Sid). The complete list is available from the link above.

Debian Stable:

  count MIME type
  ----- -----------------------
     32 text/plain
     30 audio/mpeg
     29 image/png
     28 image/jpeg
     27 application/ogg
     26 audio/x-mp3
     25 image/tiff
     25 image/gif
     22 image/bmp
     22 audio/x-wav
     20 audio/x-flac
     19 audio/x-mpegurl
     18 video/x-ms-asf
     18 audio/x-musepack
     18 audio/x-mpeg
     18 application/x-ogg
     17 video/mpeg
     17 audio/x-scpls
     17 audio/ogg
     16 video/x-ms-wmv

Debian Testing:

  count MIME type
  ----- -----------------------
     33 text/plain
     32 image/png
     32 image/jpeg
     29 audio/mpeg
     27 image/gif
     26 image/tiff
     26 application/ogg
     25 audio/x-mp3
     22 image/bmp
     21 audio/x-wav
     19 audio/x-mpegurl
     19 audio/x-mpeg
     18 video/mpeg
     18 audio/x-scpls
     18 audio/x-flac
     18 application/x-ogg
     17 video/x-ms-asf
     17 text/html
     17 audio/x-musepack
     16 image/x-xbitmap

Debian Unstable:

  count MIME type
  ----- -----------------------
     31 text/plain
     31 image/png
     31 image/jpeg
     29 audio/mpeg
     28 application/ogg
     27 image/gif
     26 image/tiff
     26 audio/x-mp3
     23 audio/x-wav
     22 image/bmp
     21 audio/x-flac
     20 audio/x-mpegurl
     19 audio/x-mpeg
     18 video/x-ms-asf
     18 video/mpeg
     18 audio/x-scpls
     18 application/x-ogg
     17 audio/x-musepack
     16 video/x-ms-wmv
     16 video/x-msvideo

I am told that PackageKit can provide an API to access the kind of information mentioned in DEP-11. I have not yet had time to look at it, but hope the PackageKit people in Debian are on top of these issues.

Update 2013-01-16 13:35: Updated numbers after discovering a typo in my script.

Tags: debian, english.
Using modalias info to find packages handling my hardware
15th January 2013

Yesterday, I wrote about the modalias values provided by the Linux kernel following my hope for better dongle support in Debian. Using this knowledge, I have tested how modalias values attached to package names can be used to map packages to hardware. This allow the system to look up and suggest relevant packages when I plug in some new hardware into my machine, and replace discover and discover-data as the database used to map hardware to packages.

I create a modaliases file with entries like the following, containing package name, kernel module name (if relevant, otherwise the package name) and globs matching the relevant hardware modalias.

Package: package-name
Modaliases: module(modaliasglob, modaliasglob, modaliasglob)

It is fairly trivial to write code to find the relevant packages for a given modalias value using this file.

An entry like this would suggest the video and picture application cheese for many USB web cameras (interface bus class 0E01):

Package: cheese
Modaliases: cheese(usb:v*p*d*dc*dsc*dp*ic0Eisc01ip*)

An entry like this would suggest the pcmciautils package when a CardBus bridge (bus class 0607) PCI device is present:

Package: pcmciautils
Modaliases: pcmciautils(pci:v*d*sv*sd*bc06sc07i*)

An entry like this would suggest the package colorhug-client when plugging in a ColorHug with USB IDs 04D8:F8DA:

Package: colorhug-client
Modaliases: colorhug-client(usb:v04D8pF8DAd*)

I believe the format is compatible with the format of the Packages file in the Debian archive. Ubuntu already uses their Packages file to store their mappings from packages to hardware.

By adding a XB-Modaliases: header in debian/control, any .deb can announce the hardware it support in a way my prototype understand. This allow those publishing packages in an APT source outside the Debian archive as well as those backporting packages to make sure the hardware mapping are included in the package meta information. I've tested such header in the pymissile package, and its modalias mapping is working as it should with my prototype. It even made it to Ubuntu Raring.

To test if it was possible to look up supported hardware using only the shell tools available in the Debian installer, I wrote a shell implementation of the lookup code. The idea is to create files for each modalias and let the shell do the matching. Please check out and try the hw-support-lookup shell script. It run without any extra dependencies and fetch the hardware mappings from the Debian archive and the subversion repository where I currently work on my prototype.

When I use it on a machine with a yubikey inserted, it suggest to install yubikey-personalization:

% ./hw-support-lookup

When I run it on my Thinkpad X40 with a PCMCIA/CardBus slot, it propose to install the pcmciautils package:

% ./hw-support-lookup

If you know of any hardware-package mapping that should be added to my database, please tell me about it.

It could be possible to generate several of the mappings between packages and hardware. One source would be to look at packages with kernel modules, ie packages with *.ko files in /lib/modules/, and extract their modalias information. Another would be to look at packages with udev rules, ie packages with files in /lib/udev/rules.d/, and extract their vendor/model information to generate a modalias matching rule. I have not tested any of these to see if it work.

If you want to help implementing a system to let us propose what packages to install when new hardware is plugged into a Debian machine, please send me an email or talk to me on #debian-devel.

Tags: debian, english, isenkram.
Modalias strings - a practical way to map "stuff" to hardware
14th January 2013

While looking into how to look up Debian packages based on hardware information, to find the packages that support a given piece of hardware, I refreshed my memory regarding modalias values, and decided to document the details. Here are my findings so far, also available in the Debian Edu subversion repository:

Modalias decoded

This document try to explain what the different types of modalias values stands for. It is in part based on information from <URL: >, <URL: >, <URL: > and <URL: >.

The modalias entries for a given Linux machine can be found using this shell script:

find /sys -name modalias -print0 | xargs -0 cat | sort -u

The supported modalias globs for a given kernel module can be found using modinfo:

% /sbin/modinfo psmouse | grep alias:
alias:          serio:ty05pr*id*ex*
alias:          serio:ty01pr*id*ex*

PCI subtype

A typical PCI entry can look like this. This is an Intel Host Bridge memory controller:


This represent these values:

 v   00008086  (vendor)
 d   00002770  (device)
 sv  00001028  (subvendor)
 sd  000001AD  (subdevice)
 bc  06        (bus class)
 sc  00        (bus subclass)
 i   00        (interface)

The vendor/device values are the same values outputted from 'lspci -n' as 8086:2770. The bus class/subclass is also shown by lspci as 0600. The 0600 class is a host bridge. Other useful bus values are 0300 (VGA compatible card) and 0200 (Ethernet controller).

Not sure how to figure out the interface value, nor what it means.

USB subtype

Some typical USB entries can look like this. This is an internal USB hub in a laptop:


Here is the values included in this alias:

 v    1D6B  (device vendor)
 p    0001  (device product)
 d    0206  (bcddevice)
 dc     09  (device class)
 dsc    00  (device subclass)
 dp     00  (device protocol)
 ic     09  (interface class)
 isc    00  (interface subclass)
 ip     00  (interface protocol)

The 0900 device class/subclass means hub. Some times the relevant class is in the interface class section. For a simple USB web camera, these alias entries show up:


Interface class 0E01 is video control, 0E02 is video streaming (aka camera), 0101 is audio control device and 0102 is audio streaming (aka microphone). Thus this is a camera with microphone included.

ACPI subtype

The ACPI type is used for several non-PCI/USB stuff. This is an IR receiver in a Thinkpad X40:


The values between the colons are IDs.

DMI subtype

The DMI table contain lots of information about the computer case and model. This is an entry for a IBM Thinkpad X40, fetched from /sys/devices/virtual/dmi/id/modalias:


The values present are

 bvn  IBM            (BIOS vendor)
 bvr  1UETB6WW(1.66) (BIOS version)
 bd   06/15/2005     (BIOS date)
 svn  IBM            (system vendor)
 pn   2371H4G        (product name)
 pvr  ThinkPadX40    (product version)
 rvn  IBM            (board vendor)
 rn   2371H4G        (board name)
 rvr  NotAvailable   (board version)
 cvn  IBM            (chassis vendor)
 ct   10             (chassis type)
 cvr  NotAvailable   (chassis version)

The chassis type 10 is Notebook. Other interesting values can be found in the dmidecode source:

  3 Desktop
  4 Low Profile Desktop
  5 Pizza Box
  6 Mini Tower
  7 Tower
  8 Portable
  9 Laptop
 10 Notebook
 11 Hand Held
 12 Docking Station
 13 All In One
 14 Sub Notebook
 15 Space-saving
 16 Lunch Box
 17 Main Server Chassis
 18 Expansion Chassis
 19 Sub Chassis
 20 Bus Expansion Chassis
 21 Peripheral Chassis
 22 RAID Chassis
 23 Rack Mount Chassis
 24 Sealed-case PC
 25 Multi-system
 26 CompactPCI
 27 AdvancedTCA
 28 Blade
 29 Blade Enclosing

The chassis type values are not always accurately set in the DMI table. For example my home server is a tower, but the DMI modalias claim it is a desktop.

SerIO subtype

This type is used for PS/2 mouse plugs. One example is from my test machine:


The values present are

  ty  01  (type)
  pr  00  (prototype)
  id  00  (id)
  ex  00  (extra)

This type is supported by the psmouse driver. I am not sure what the valid values are.

Other subtypes

There are heaps of other modalias subtypes according to file2alias.c. There is the rest of the list from that source: amba, ap, bcma, ccw, css, eisa, hid, i2c, ieee1394, input, ipack, isapnp, mdio, of, parisc, pcmcia, platform, scsi, sdio, spi, ssb, vio, virtio, vmbus, x86cpu and zorro. I did not spend time documenting all of these, as they do not seem relevant for my intended use with mapping hardware to packages when new stuff is inserted during run time.

Looking up kernel modules using modalias values

To check which kernel modules provide support for a given modalias, one can use the following shell script:

  for id in $(find /sys -name modalias -print0 | xargs -0 cat | sort -u); do \
    echo "$id" ; \
    /sbin/modprobe --show-depends "$id"|sed 's/^/  /' ; \

The output can look like this (only the first few entries as the list is very long on my test machine):

    insmod /lib/modules/2.6.32-5-686/kernel/drivers/acpi/ac.ko 
  FATAL: Module acpi:device: not found.
    insmod /lib/modules/2.6.32-5-686/kernel/drivers/char/nvram.ko 
    insmod /lib/modules/2.6.32-5-686/kernel/drivers/leds/led-class.ko 
    insmod /lib/modules/2.6.32-5-686/kernel/net/rfkill/rfkill.ko 
    insmod /lib/modules/2.6.32-5-686/kernel/drivers/platform/x86/thinkpad_acpi.ko 
    insmod /lib/modules/2.6.32-5-686/kernel/lib/crc-ccitt.ko 
    insmod /lib/modules/2.6.32-5-686/kernel/net/irda/irda.ko 
    insmod /lib/modules/2.6.32-5-686/kernel/drivers/net/irda/nsc-ircc.ko 

If you want to help implementing a system to let us propose what packages to install when new hardware is plugged into a Debian machine, please send me an email or talk to me on #debian-devel.

Update 2013-01-15: Rewrite "cat $(find ...)" to "find ... -print0 | xargs -0 cat" to make sure it handle directories in /sys/ with space in them.

Tags: debian, english, isenkram.
Moved the pymissile Debian packaging to collab-maint
10th January 2013

As part of my investigation on how to improve the support in Debian for hardware dongles, I dug up my old Mark and Spencer USB Rocket Launcher and updated the Debian package pymissile to make sure udev will fix the device permissions when it is plugged in. I also added a "Modaliases" header to test it in the Debian archive and hopefully make the package be proposed by jockey in Ubuntu when a user plug in his rocket launcher. In the process I moved the source to a git repository under collab-maint, to make it easier for any DD to contribute. Upstream is not very active, but the software still work for me even after five years of relative silence. The new git repository is not listed in the uploaded package yet, because I want to test the other changes a bit more before I upload the new version. If you want to check out the new version with a .desktop file included, visit the gitweb view or use "git clone git://".

Tags: debian, english, isenkram, robot.
Lets make hardware dongles easier to use in Debian
9th January 2013

One thing that annoys me with Debian and Linux distributions in general, is that there is a great package management system with the ability to automatically install software packages by downloading them from the distribution mirrors, but no way to get it to automatically install the packages I need to use the hardware I plug into my machine. Even if the package to use it is easily available from the Linux distribution. When I plug in a LEGO Mindstorms NXT, it could suggest to automatically install the python-nxt, nbc and t2n packages I need to talk to it. When I plug in a Yubikey, it could propose the yubikey-personalization package. The information required to do this is available, but no-one have pulled all the pieces together.

Some years ago, I proposed to use the discover subsystem to implement this. The idea is fairly simple:

I am not sure what the best way to implement this is, but my initial idea was to use dbus events to discover new hardware, the discover database to find packages and PackageKit to install packages.

Yesterday, I found time to try to implement this idea, and the draft package is now checked into the Debian Edu subversion repository. In the process, I updated the discover-data package to map the USB ids of LEGO Mindstorms and Yubikey devices to the relevant packages in Debian, and uploaded a new version 2.2013.01.09 to unstable. I also discovered that the current discover package in Debian no longer discovered any USB devices, because /proc/bus/usb/devices is no longer present. I ported it to use libusb as a fall back option to get it working. The fixed package version 2.1.2-6 is now in experimental (didn't upload it to unstable because of the freeze).

With this prototype in place, I can insert my Yubikey, and get this desktop notification to show up (only once, the first time it is inserted):

For this prototype to be really useful, some way to automatically install the proposed packages by pressing the "Please install program(s)" button should to be implemented.

If this idea seem useful to you, and you want to help make it happen, please help me update the discover-data database with mappings from hardware to Debian packages. Check if 'discover-pkginstall -l' list the package you would like to have installed when a given hardware device is inserted into your computer, and report bugs using reportbug if it isn't. Or, if you know of a better way to provide such mapping, please let me know.

This prototype need more work, and there are several questions that should be considered before it is ready for production use. Is dbus the correct way to detect new hardware? At the moment I look for HAL dbus events on the system bus, because that is the events I could see on my Debian Squeeze KDE desktop. Are there better events to use? How should the user be notified? Is the desktop notification mechanism the best option, or should the background daemon raise a popup instead? How should packages be installed? When should they not be installed?

If you want to help getting such feature implemented in Debian, please send me an email. :)

Tags: debian, english, isenkram.
New IRC channel for LEGO designers using Debian
2nd January 2013

During Christmas, I have worked a bit on the Debian support for LEGO Mindstorm NXT. My son and I have played a bit with my NXT set, and I discovered I had to build all the tools myself because none were already in Debian Squeeze. If Debian support for LEGO is something you care about, please join me on the IRC channel #debian-lego (server There is a lot that could be done to improve the Debian support for LEGO designers. For example both CAD software and Mindstorm compilers are missing. :)

Update 2012-01-03: A project page including links to Lego related packages is now available.

Tags: debian, english, robot.
Lenker for 2013-01-01
1st January 2013

Her er noen lenker til tekster jeg har satt pris på å lese den siste måneden.

Og et godt nytt år til dere alle!

Tags: bankid, lenker, norsk, opphavsrett, personvern.

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