Thomas Petazzoni – Page 32

Bootlin at the Android Builders Summit and the Embedded Linux Conference: one talk and video recording

A good part of the Bootlin team will be in San Francisco (actually, not in San Francisco, but in the Bay Area) from February, 13th to 17th for the Android Builders Summit and the Embedded Linux Conference.

The Android Builders Summit is the second edition of this conference dedicated to Android system development (and not application development). Compared to last year, the conference has been extended to three parallel tracks during two days. There are many talks about Android customization, Android internals, Android porting, usage of Android in specific markets (medical devices, vehicle infotainment), etc. A lot of useful talks for developers working at the Android system level.

The Embedded Linux Conference is now a well-established conference. Again for this 2012 edition, there will be three parallel tracks during three days. There will be talks about many, many topics: performance and optimization, power management, build systems, drivers for various types of devices, multimedia, ARM kernel support and much more.

I will be giving a talk about Buildroot: A Nice, Simple and Efficient Embedded Linux Build System on the second day of the conference. The aim of the talk is to give a status on where Buildroot is, three years after a maintainer was chosen and a big clean up work was started. The project has changed a lot compared to its state three years ago, so I thought it would be nice to make a status on where Buildroot and where it is going.

With my colleagues Grégory Clément and Maxime Ripard, we will also record all the talks from the Embedded Linux Conference in order to put the videos online, freely available, after the conference, as we have done for many past conferences.

We hope to meet you in San Francisco for the Android Builders Summit and the Embedded Linux Conference!

Announcing our “Android System Development” training

Android Robot For multiple years, Bootlin has provided two typical training courses for embedded Linux developers: an Embedded Linux system development course that focuses on the basics for embedded Linux development (bootloader and kernel configuration, compiling and usage, system integration and build systems, cross-compiling, filesystems, application development and debugging, etc.) and an embedded Linux kernel and driver development course that focuses on kernel and driver development (kernel APIs for drivers, character drivers, device model, power management, kernel porting, etc.). In total, we have given dozens of editions of these sessions in multiple locations all around the world. We have kept our commitment to release all the training materials under a free license (the Creative Commons CC-BY-SA license), and they are therefore freely accessible for anyone at /docs/.

We are now announcing a new course, called Android System Development. It is a four day training session that targets engineers who need to develop embedded systems with Google Android.

Through theory and practical labs, the course makes you familiar with compiling and booting Android, with adapting Android to support a new embedded board (assuming that it is already supported by the Linux kernel), and with building a real system through accessing specific hardware, customizing the filesystem and using debugging techniques. See the complete agenda. The training materials for this session will also be made available under the same Creative Commons CC-BY-SA license.

If you are interested in this training session, you can:

Join the public session organized in Toulouse, France, on June 11-14, 2012.
Order an on-site training session to be held at your location. See registration details.

This training course will be given by our engineer Maxime Ripard who has gained Android experience by working at Archos on Android tablets, by making Android work on multiple TI OMAP3 based platforms and also by participating to the Android Builders Summit conference.

Do not hesitate to contact us for further details about this new training course.

Bootlin at FOSDEM: two talks and video recording

I'm going to FOSDEM As usual, Bootlin will again be present at the FOSDEM conference in Brussels, on February, 4th and February 5th. We will of course mostly be attending the Embedded DevRoom, with multiple talks around development in the embedded space.

We will also be giving two talks this year:

My colleague Maxime Ripard will be giving a talk about IIO, a new subsystem for I/O devices. In short, IIO is a new subsystem in the kernel to write drivers for devices like Analog-to-Digital converters. Maxime has worked on a driver inside the IIO subsystem for the internal ADCs of the AT91 processors from Atmel, and will base his talk mostly on the experience developing this driver. This talk will take place on Saturday, 12:00 AM to 1:00 PM in the Lameere room.
I will be giving a talk on Using Qt for non-graphical applications. It is a talk that has already been given at the Embedded Linux Conference Europe, but the audience of FOSDEM and ELCE being quite different, we have chosen to propose it for FOSDEM as well, and it got accepted. This talk will take place on Sunday, 1:00 PM to 2:00 PM in the Lameere room.

There are also other talks that are worth noting: a SoC power management talk from Jean Pihet who works on OMAP power management support in the Linux kernel, a talk about OpenCores and OpenRISC, a talk about Safe Upgrade of Embedded Systems by Arnout Vandecappelle, who contributes a lot to Buildroot, and also other talks about OpenWRT, Yocto, licensing issues in Android, the EFL libraries, and more.

We will also be carrying our camcorder to video record those talks. We are trying to see with the FOSDEM organization team if it possible to record the audio directly from the room sound systems in order to provide better audio quality in our videos.

If you happen to be at FOSDEM, we’d be very happy to meet you!

Buildroot Developer Day, Brussels edition

Around each FOSDEM conference and Embedded Linux Conference Europe event, we have been organizing a Buildroot Developer Day for a few years, in order to gather some developers and users of the Buildroot build system, in order to discuss the development of Buildroot, its features, development process, design, and more.

In Prague at the last Embedded Linux Conference Europe in October 2011, we had a very interesting meeting that gathered developers from other build systems (OE-lite, OpenBricks and PXTdist), and we published a report of this meeting.

The next Buildroot Developer Day will take place on Friday, 3rd February, just before the FOSDEM conference, in Brussels. This is the first meeting that will gather such a number of Buildroot developers: Peter Korsgaard (Buildroot maintainer), Arnout Vandecapelle (developer from Essensium/Mind, who has been contributing a lot to Buildroot lately), Thomas De Schampheleire (also a big contributor in the last year or so), Luca Ceresoli, Yann E. Morin (developer of Crosstool-NG), my colleague Maxime Ripard (who contributed package enhancements and improvements of the package infrastructure) and myself.

This meeting is open to all Buildroot developers and users, and will take place in a location easily accessible in the center of Brussels. Do not hesitate to contact me at thomas.petazzoni@bootlin.com if you want to take part to this meeting.

mkenvimage: a tool to generate a U-Boot environment binary image

Many embedded devices these days use the U-Boot bootloader. This bootloader stores its configuration into an area of the flash called the environment that can be manipulated from within U-Boot using the printenv, setenv and saveenv commands, or from Linux using the fw_printenv and fw_setenv userspace utilities provided with the U-Boot source code.

This environment is typically stored in a specific flash location, defined in the board configuration header in U-Boot. The environment is basically stored as a sequence of null-terminated strings, with a little header containing a checksum at the beginning.

While this environment can easily be manipulated from U-Boot or from Linux using the above mentioned commands, it is sometimes desirable to be able to generate a binary image of an environment that can be directly flashed next to the bootloader, kernel and root filesystem into the device’s flash memory. For example, on AT91 devices, the SAM-BA utility provided by Atmel is capable of completely reflashing an AT91 based system connected through the serial port of the USB device port. Or, in factory, initial flashing of devices typically takes place either through specific CPU monitors, or through a JTAG interface. For all of these cases, having a binary environment image is desirable.

David Wagner, who has been an intern with us at Bootlin from April to September 2011, has written a utility called mkenvimage which just does this: generate a valid binary environment image from a text file describing the key=value pairs of the environment. This utility has been merged into the U-Boot Git repository (see the commit) and will therefore be part of the next U-Boot release.

With mkenvimage you can write a text file uboot-env.txt describing the environment, like:

bootargs=console=ttyS0,115200
bootcmd=tftp 22000000 uImage; bootm
[...]

Then use mkenvimage as follows:

./tools/mkenvimage -s 0x4200 -o uboot-env.bin uboot-env.txt

The -s option allows to specify the size of the image to create. It must match the size of the flash area reserved for the U-Boot environment. Another option worth having in mind is -r, which must be used when there are two copies of the environment stored in the flash thanks to the CONFIG_ENV_ADDR_REDUND and CONFIG_ENV_SIZE_REDUND. Unfortunately, U-Boot has chosen to have a different environment layout in those two cases, so you must tell mkenvimage whether you’re using a redundant environment or a single environment.

This utility has proven to be really useful, as it allows to automatically reflash a device with an environment know to work. It also allows to very easily generate a different environment image per-device, for example to contain the device MAC address and/or the device serial number.

Buildroot 2011.11 released: details on new features

As planned, Buildroot 2011.11 has been released at the end of November. You can download this release as a tarball or through the Git repository.

This release brings a set of new features on which I thought it would be nice to give some details.

The `file` and `local` site method

Each package in Buildroot defines from where the source code for the particular component being built is fetched. Buildroot has of course always supported fetching a tarball from HTTP of FTP servers. Later on, Buildroot has added support for fetching from Git, Subversion and Bazaar repositories, for example by doing:

MYPKG_SITE = http://somelocation.com/svn/foobar/trunk
MYPKG_SITE_METHOD = svn

MYPKG_SITE = git://somelocation.com/foobar.git

The <pkg>_SITE_METHOD variable allows to define the fetching method. When not specified, Buildroot tries to guess it from the <pkg>_SITE value. Of course, in ambiguous cases such as Subversion or Git repositories over HTTP (as shown in the first example), the <pkg>_SITE_METHOD must be specified.

This new version of Buildroot brings two new site methods: file and local.

The file site method allows to specify the location of a local tarball as the source code for the component to be built. For example:

MYPKG_SITE = /opt/software/something-special-1.0.tar.gz
MYPKG_SITE_METHOD = file

This can be useful for internal software that isn’t publicly available on a HTTP or FTP server or in a revision control system. This new site method was added by David Wagner, who has been an intern at Bootlin between April and September this year.

The new local site method allows to specify the location of the source code to be built as a local directory. Buildroot will automatically copy the contents of this directory into the build directory of the component and build it from here. This is very useful because it allows to version control your source code as you wish, make changes to it, and easily tell Buildroot to rebuild your component. Note that the copy is using rsync so that further copies are very fast (see the pkg-reconfigure and pkg-rebuild targets below). An example of using the local site method:

MYPKG_SITE = /opt/software/something-special/
MYPKG_SITE_METHOD = local

This new site method has been implemented by myself, as the result from my experience of using Buildroot with various Bootlin customers.

The source directory override mechanism

The local site method described above is great for packaging special components that are specific to the embedded device one is working on, like the end-user application, or special internal libraries, etc.

However, there are cases where it is needed to work with a specific version of an open-source component. This is typically the case for the Linux kernel or the chosen bootloader (U-Boot, Barebox) or with other components. In that case, one may want to keep using Buildroot to build those components, but tell Buildroot to fetch the source code from a different location than the official tarball of the component. This is what the source directory override mechanism provide.

For example, if you want Buildroot to use the source code of the Linux kernel from /opt/project/linux/ rather than download it from a Git repository or as a tarball, you can write the following variable definition in a board/company/project/local.mk file:

LINUX_OVERRIDE_SRCDIR = /opt/project/linux

Then, you reference this file through the BR2_PACKAGE_OVERRIDE_FILE option, in Build options -> location of a package override file. When building the Linux kernel, Buildroot will copy the source code from /opt/project/linux into the kernel build directory, output/build/linux-VERSION/ and then start the build process of the kernel.

Basically, this mechanism is exactly like the local site method described previously, except that it is possible to override the source directory of a package without modifying the package .mk file, which is nice for open-source packages supported in Buildroot but that require local modifications.

To summarize, here is my recommendation on how to use Buildroot for packages that require project-specific modifications:

You are using an existing open-source component on which you make some tiny bug fixes or modifications. In this case, the easiest solution is to add additional patches to the package directory, in package/<thepackage>/.
You are using an existing open-source component, but are making major changes to it, that require proper version control outside of Buildroot. In this case, using the source directory override feature is recommended: it allows to keep the Buildroot package .mk file unmodified while still using your custom source code for the package.
You have project-specific libraries or applications and want to integrate them in the build. My commendation is to version control them outside of Buildroot, and then create Buildroot packages for them using the local site method. Note that in the pkg_SITE variable, you can use the $(TOPDIR) variable to reference the top source directory of Buildroot. I for example often use MYAPP_SITE = $(TOPDIR)/../myapplication/.

The `<pkg>-rebuild` and `<pkg>-reconfigure` targets

For a long time, when one wanted to completely rebuild a given package from scratch, a possibility was has been to remove its build directory completely before restarting the build process:

rm -rf output/build/mypackage-1.0/
make

Or, using the -dirclean target available for each package:

make avahi-dirclean
make

As these commands remove completely the build directory, the build process is restarted from the beginning: extracting the source code, patching the source code, configuring, compiling, installing.

In 2011.11, we have added two new per-package targets to make it easy to use Buildroot during the development of components:

make mypkg-reconfigure will restart the build process of mypkg from the configuration step (the source code is not re-extracted or repatched, so modifications made to the build directory are preserved)
make mypkg-rebuild will restart the build process of mypkg from the compilation step (the source code is not re-extracted or repatched, the configuration step is not redone)

So, a typical usage could be:

emacs output/build/mypkg-1.0/src/foobar.c
make foobar-rebuild

However, beware that all build directories are removed when you do make clean, so the above example is only useful for quick testing of changes.

The case where the -reconfigure and -rebuild are really useful is in combination with the local site method or the source override directory mechanism. In this case, when pkg-reconfigure or pkg-rebuild is invoked, a synchronization of the source code is done between the source directory and the build directory is done before restarting the build.

Let’s take the example of a package named mypkg for which package/mypkg/mypkg.mk contains:

MYPKG_SITE = /opt/mypkg
MYPKG_SITE_METHOD = local

Then, to work on your package, you can simply do

emacs /opt/mypkg/foobar.c    # Edit as usual your project
make mypkg-rebuild           # Synchronizes the source code from
                             # /opt/mypkg to the build directory
                             # and restart the build

Integration of real-time extensions

In this 2011.11, an interesting addition is the integration of the Xenomai and RTAI real-time extensions to the Linux kernel. The Xenomai integration was initially proposed by Thomas de Schampheleire and then extended by myself, and I have also added the RTAI integration. This integration allows to seamlessly integrate the kernel patching process and the compilation of the required userspace libraries for those real-time extensions.

Conversion of the documentation to asciidoc

Back in 2004, one of my first contribution to Buildroot was to start writing documentation. At the time, the amount of documentation was small, so a single and simple HTML document was sufficient. Nowadays, Buildroot documentation has been extended significantly, and will have to be extended even further in the future. The approach of a single raw HTML document was no longer up to the task.

Therefore, I have worked on converting the existing documentation over to the asciidoc format. This allows us to split the source of the documentation in several files, for easier edition, and allows to generates a documentation in multiple formats: single HTML, split HTML, raw text or PDF.

Just run make manual in Buildroot 2011.11 to generate the manual. Note that the version available on the website is still the old HTML version, but it should soon be updated to the new asciidoc version.

Bootlin contributions

Bootlin has again contributed to this Buildroot release:

$ git shortlog -sen 2011.08..2011.11 | head -12
   126	Peter Korsgaard
   104	Gustavo Zacarias
    62	Thomas Petazzoni, from Bootlin
    27	Yann E. MORIN
    21	Sven Neumann
    13	Yegor Yefremov
    10	Thomas De Schampheleire
     7	H Hartley Sweeten
     5	Frederic Bassaler
     4	Arnout Vandecappelle (Essensium/Mind)
     4	Maxime Ripard, from Bootlin
     3	Baruch Siach

Our contributions have been:

Implementation of the source directory override mechanism
Implementation of the local and file site methods
Implementation of the pkg-rebuild and pkg-reconfigure targets
Conversion of the documentation to asciidoc and documentation improvements
Various improvements for external toolchain support: optimization of the toolchain extraction and copy (reduced build time), integration of the support of the CodeSourcery x86 toolchains, update of all CodeSourcery toolchains to the latest available versions
Removed useless arguments from the CMAKETARGETS, AUTOTARGETS and GENTARGETS macros, used by all packages in Buildroot. Instead, such pieces of information are automatically figured out from the package .mk file location in the source tree
Added the cifs-utils package (for mounting CIFS network filesystems), the libplayer package, the picocom package.
Cleanup, improve and merge the Xenomai integration done by Thomas de Schampheleire, and implement the RTAI integration
Did a lot of cleanup in the source tree by creating a new support/ directory to contain various tools and scripts needed by Buildroot that were spread over the rest of the tree: the kconfig source code, the special libtool patches, various scripts, etc.

Next release cycle and next Buildroot meeting

The next release cycle has already started. After the meeting in Prague, it was decided that Peter Korsgaard (Buildroot maintainer) would maintain a next branch between the -rc1 and the final version of every release, in order to keep merging the new features for the next release while debugging the current release. This next branch for 2012.02 has already been merged. For example, the addition of the scp and Mercurial site methods has already been merged for 2012.02, as well as numerous other package updates.

On my side, besides usual package updates, I’d like to focus my work for this 2012.02 cycle on improving the testing coverage and on improving the documentation. My colleague Maxime Ripard is working on integrating systemd into Buildroot, as an alternate init mechanism.

The Buildroot community will also be organizing its next meeting in Brussels, on Friday February, 3rd 2012, right before the FOSDEM conference. Buildroot users and developers are invited to join, just contact us through the Buildroot mailing list.

Embedded Linux Conference Europe 2011 videos

One week after the end of the Embedded Linux Conference Europe 2011, we are pleased to release the videos of all talks that took place during this event. We would like to thank the Linux Foundation for allowing us to record those talks and to share freely the resulting videos on-line, and also thank the Clarion Congress Hotel technical staff for helping us with technical details related to video recording.

Below, you’ll find 51 videos, in both a 1920×1080 HD format and a reduced 800×450 format. In total, it represents 28 GB of video, for a duration of 2214 minutes, that is more of 36 hours of video. We hope that you will enjoy those videos and that these will be useful to those who couldn’t attend the conference.

Jim Zemlin
Executive Director of The Linux Foundation
Imagine a World Without Linux
Video (24 minutes):
full HD (220M), 450×800 (76M)

Linus Torvalds, Alan Cox, Thomas Gleixner, Paul McKenney
moderated by Lennart Poettering
Kernel Developer Panel
Video (55 minutes):
full HD (622M), 450×800 (191M)

Zach Pfeffer
Linaro
Linaro’s Android Platform
Video (45 minutes):
full HD (604M), 450×800 (164M)

Thomas Gleixner
Linutronix
State of PREEMPT_RT
Video (46 minutes):
full HD (374M), 450×800 (147M)

Jessica Zhang
Intel
The Yocto Project Eclipse plug-in: An effective IDE environment for both Embedded Application and System developers
Video (45 minutes):
full HD (431M), 450×800 (118M)

Satoru Ueda
Sony Corporation / Japan OSS Promotion Forum
Contributing to the Community? Does your Manager Support You?
Video (42 minutes):
full HD (556M), 450×800 (140M)

Benjamin Zores
Alcatel-Lucent
Embedded Linux Optimization Techniques: How Not To Be Slow
Slides
Video (44 minutes):
full HD (328M), 450×800 (125M)

Ohad Ben-Cohen
Texas Instruments
Remote Processor Messaging
Slides
Video (48 minutes):
full HD (433M), 450×800 (131M)

Jeff Osier-Mixon
Intel
Collaborative Initiatives in Embedded Linux
Video (26 minutes):
full HD (266M), 450×800 (73M)

Karim Yaghmour
Opersys Inc.
Leveraging Android’s Linux Heritage
Video (51 minutes):
full HD (419M), 450×800 (168M)

Pierre Tardy
Intel
Using pytimechart For Real World Analysis
Slides
Video (51 minutes):
full HD (495M), 450×800 (132M)

Arnd Bergmann
Linaro
Optimizations for Cheap Flash Media
Video (44 minutes):
full HD (524M), 450×800 (146M)

Vitaly Wool
Sony Ericsson
Saving Power with Wi-Fi: How to Prolong Your Battery Life and Still Stay Connected
Slides
Video (50 minutes):
full HD (371M), 450×800 (143M)

David Stewart
Intel
Developing Embedded Linux Devices Using the Yocto Project and What’s new in 1.1
Slides
Video (47 minutes):
full HD (370M), 450×800 (124M)

Tetsuyuki Kobayashi
Kyoto Micro Computer
Android is NOT Just “Java on Linux”
Slides
Video (37 minutes):
full HD (542M), 450×800 (129M)

Thomas Petazzoni
Bootlin
Using Buildroot For a Real Project
Slides
Video (55 minutes):
full HD (408M), 450×800 (156M)

Tim Bird
Sony Network Entertainment
Status of Embedded Linux BoFs
Slides
Video (60 minutes):
full HD (877M), 450×800 (213M)

Lauro Ramos Venancio and Samuel Ortiz
Instituto Nokia de Tecnologia, Intel
The Linux NFC Subsystem
Slides
Video (31 minutes):
full HD (229M), 450×800 (87M)

David Anders
Texas Instruments
Board Bringup: LCD and Display Interfaces
Slides
Video (39 minutes):
full HD (242M), 450×800 (98M)

Antti Aumo
President of Global Solutions at Ixonos
Re-Defining the Cloud Phone
Video (32 minutes):
full HD (360M), 450×800 (108M)

Dirk Hohndel
Chief Linux and Open Source Technologist at Intel
Reflection on 20 Years of Linux
Video (30 minutes):
full HD (235M), 450×800 (92M)

Grant Likely
Secret Lab
Device Tree Status Report
Video (51 minutes):
full HD (775M), 450×800 (178M)

Laurent Pinchart
Ideas on Board
Success Story of the Open-Source Camera Stack: The Nokia N9 Case
Slides
Video (48 minutes):
full HD (308M), 450×800 (120M)

Avinash Mahadeva and Vishwanth Sripathy
Texas Instuments
SOC Power Management – Debugging and Optimization Techniques
Video (41 minutes):
full HD (288M), 450×800 (108M)

Rafael J. Wysocki
Faculty of Physics, U. Warsaw / SUSE Labs
Power Management Using PM Domains on SH7372
Slides
Video (46 minutes):
full HD (692M), 450×800 (157M)

Sascha Hauer
Pengutronix e.K.
A Generic Clock Framework in the Kernel: Why We Need It and Why We Still Don’t Have It
Video (45 minutes):
full HD (345M), 450×800 (134M)

Ruud Derwig
Synopsys
Android Platform Optimizations
Slides
Video (43 minutes):
full HD (266M), 450×800 (105M)

Inki Dae
Samsung Electronics
DRM Driver Development For Embedded Systems
Slides
Video (22 minutes):
full HD (367M), 450×800 (91M)

Lorenzo Pieralisi
ARM Ltd.
Consolidating Linux Power Management on ARM Multiprocessor Systems
Slides
Video (46 minutes):
full HD (283M), 450×800 (113M)

Thomas Petazzoni
Bootlin
Using Qt For Non-Graphical Applications
Slides
Video (49 minutes):
full HD (340M), 450×800 (124M)

Marek Szyprowski and Kyungmin Park
Samsung Electronics
ARM DMA-Mapping Framework Redesign and IOMMU Integration
Slides
Video (49 minutes):
full HD (790M), 450×800 (195M)

Keerthyd Jagadeesh and Vishwanath Sripathy
Texas Instruments
Thermal Framework for ARM based SOCs
Video (42 minutes):
full HD (316M), 450×800 (113M)

Marc Titinger
ST Microelectronics
Efficient JTAG-Based Linux Kernel Debugging
Slides
Video (57 minutes):
full HD (382M), 450×800 (141M)

Tsugikazu Shibata
NEC and Linux Foundation Board Member
Toward the Long Term Stable Kernel tree for The Embedded Industry
Video (32 minutes):
full HD (606M), 450×800 (145M)

Lisko Lappalainen
MontaVista Software
Secure Virtualization in Automotive
Video (40 minutes):
full HD (301M), 450×800 (116M)

Jeff Osier-Mixon
Intel
Yocto Project Community BoFs
Video (60 minutes):
full HD (451M), 450×800 (167M)

Jon Corbet
Editor at LWN.net
The Kernel Report: 20th Anniversary Edition
Video (28 minutes):
full HD (218M), 450×800 (88M)

Wim Coekaerts
Senior Vice President, Linux and Virtualization Engineering at Oracle
Engineered Systems With Linux
Video (21 minutes):
full HD (175M), 450×800 (68M)

Andrea Gallo
ST-Ericsson
ARM Linux Kernel Alignment and Benefits For Snowball
Slides
Video (47 minutes):
full HD (394M), 450×800 (133M)

Liam Girdwood and Peter Ujfalusi
Texas Instruments
Smart Audio: Next-Generation ASoC For Smart Phones
Video (50 minutes):
full HD (367M), 450×800 (124M)

Pawel Moll
ARM Ltd.
Linux on Non-Existing SoCs
Video (52 minutes):
full HD (483M), 450×800 (143M)

Koen Kooi
The Angstrom Distribution
Integrating systemd: Booting Userspace in Less Than 1 Second
Slides
Video (44 minutes):
full HD (343M), 450×800 (125M)

Sylvain Leroy and Philippe Thierry
Grsecurity in Embedded Linux Used in Android Operating System
Slides
Video (40 minutes):
full HD (384M), 450×800 (110M)

MyungJoo Ham
Samsung Electronics
Charger Manager: Aggregating Chargers, Fuel-Gauges and Batteries
Slides
Video (33 minutes):
full HD (434M), 450×800 (109M)

Arnd Bergmann
Linaro
News From the ARM Architecture
Video (49 minutes):
full HD (421M), 450×800 (150M)

Frank Rowand
Sony Network Entertainment
How Linux PREEMPT_RT Works
Slides
Video (45 minutes):
full HD (378M), 450×800 (135M)

Catalin Marinas
ARM Ltd.
Linux Support for the ARM Large Physical Address Extensions
Slides
Video (52 minutes):
full HD (594M), 450×800 (170M)

Jim Huang
0xlab
Build Community Android Distribution and Ensure the Quality
Video (44 minutes):
full HD (472M), 450×800 (143M)

Till Jaeger
JBB Rechtsanwälte
The Case AVM v. Cybits: The GPL and Embedded Systems
Video (42 minutes):
full HD (362M), 450×800 (124M)

Darren Hart
Intel
Tuning Linux For Embedded Systems: When Less is More
Slides
Video (45 minutes):
full HD (482M), 450×800 (135M)

Wolfram Sang
Pengutronix e.K.
Developer’s Diary: It’s About Time
Video (49 minutes):
full HD (482M), 450×800 (141M)

Report from the Buildroot Developer Day

Right after the Embedded Linux Conference Europe, a new edition of the Buildroot Developer Day took place on Saturday, 29th October 2011 in Prague.

Unlike past Buildroot Developer Day that were followed only by Buildroot developers and Yann E. Morin as the crosstool-NG maintainer, this edition of the Buildroot Developer Day was followed by developers of other build systems: Robert Schwebel from PTXdist, Esben Haabendal from OE-lite and we also had the opportunity to discuss with Benjamin Zores and Davide Calvalca from OpenBricks. This made the day very interesting, even though if it was a bit less focused on Buildroot than expected.

I have written and sent a complete report of the discussions, which were about the following topics:

Expanding the send-patches.org initiative. This was an important topic, as developers of several build systems had the opportunity to discuss it during this meeting.
The testing infrastructure of Buildroot, how to improve it.
Package management. A long requested feature for Buildroot, but which would make Buildroot a lot more complicated and probably less reliable. Following this meeting, our position is to not implement such a feature and to keep Buildroot simple. Should package management be necessary, there are other build systems that implement such a feature (at the expense of higher complexity, of course).
Toolchain backend. We will soon switch to using the crosstool-NG backend as the default method of building toolchains in Buildroot. Long term, we would like to get rid of the code that builds a toolchain in Buildroot in order to factorize the efforts at the level of the crosstool-NG project.
Migration of the documentation to the asciidoc format has been accepted, and the next version of Buildroot will feature this updated documentation.
Out-of-tree build of packages. This is a very internal question to how Buildroot builds package. See the report for details.
Website improvement, because the current Buildroot website is quite ugly.
Maintenance process. We are seeing a quite significant increase in the number of contributions to Buildroot and some of these contributions are taking more and more time to get integrated. We discussed the topic and came up with a few proposals on how to improve the situation.
Host packages visible in menuconfig. Traditionally, packages built for the host are not user-selectable as Buildroot since they are just dependencies to build target packages. However, we had the case of some host packages that should be user-selectable. The principle has been agreed upon.
Per-package device file handling. A mechanism proposed by Maxime Ripard, from Bootlin, to allow each package to specify special permissions/owernships/device files to install in the target filesystem.
Relocatable toolchain and SDK. Buildroot produces a SDK (set of utilities and libraries to build applications for the target independently from Buildroot), but this SDK is currently not relocatable. We discussed the various issues to fix to make it relocatable.
Licensing report generation, which is also a feature that has been requested in the past.

All in all, it was a very interesting and motivating day, that got closed by a short visit of Prague’s center and a nice dinner. The next edition of the Buildroot Developer day will take place on Friday, 3rd 2012 in Brussels, the day before the FOSDEM conference. It is open to all Buildroot users and developers!

Regarding Buildroot itself, the maintainer Peter Korsgaard will release 2011.11-rc1 early next week, and 2011.11 by the end of November. This release will have several new useful features, which we will cover in details in a future blog post.

Back from Embedded Linux Conference Europe 2011

As we announced in a previous blog post, a large part of the Bootlin team attended the 2011 edition of the Embedded Linux Conference Europe in Prague last week.

This was the first european edition of the conference to last three days, and this was much appreciated as it gave the opportunity to attend a lot more conferences and to spend more time talking with developers of the community. My colleagues Michael Opdenacker and Maxime Ripard as well as myself really enjoyed this conference. It really allows to connect with members of the community, learn a lot of new things, and bring home a huge motivation to work on various projects. Despite a few marketing-oriented keynotes, the conference has kept its highly-technical profile, which is great.

We have recorded all the talks of the three tracks of the Embedded Linux Conference Europe (unfortunately, there wasn’t a similar video crew for the LinuxCon Europe conference which was taking place at the same time). Many of those videos should have a much higher audio quality than what we had in the past, since we could capture the audio directly for the conference room sound system. Unfortunately, one of our camcorders generates a loud noise when connected both to the audio system of the conference room and to the power adapter (this noise disappears when the camcorder is on battery). Therefore, not all conferences could be recorded with this improved audio quality. The encoding and upload of those videos has started on Sunday evening, just a few hours after landing in Toulouse when coming back from ELCE. The process is running 24/24 on two machines in parallel, and we therefore hope to be able to provide those videos online by the end of the week, or at worst at the beginning of next week.

Kernel Developer Panel. From left to right: Linus Torvalds, Paul McKenney, Alan Cox, Thomas Gleixner and the moderator, Lennart Poettring

As we also announced, I gave two talks at this Embedded Linux Conference Europe event. One on Buildroot, titled Using Buildroot for real projects, which slides are available on the elinux.org site. More than 50 persons attended the conference which seems to indicate that there is interest around Buildroot. I had a few questions but unfortunately had to stop the conference after just 2/3 questions since I had exhausted my time slot. My second conference was titled Qt for non-graphical applications, and the slides are also available on the elinux.org site. About 45-50 persons attended the conference and in this case as well, I had to speak quite fast to make the 40+ slides discussion fit within the time slot allocated for the conference, which gave only the time for a few questions at the end. Generally speaking, these talks have attracted a nice number of attendees compared to many other talks I’ve seen, so it seems that all the preparation work was not done needlessly.

Nicolas Deschene (TI) and Loïc Minier (Linaro)

If you couldn’t attend ELCE and are waiting for the videos, I’m sure you’ll also be interested by the date and locations of the next editions of the conference :

The next Embedded Linux Conference, US edition, will take place on February 14-16 2012 in Redwood City, near San Francisco in California. This is an unusual date for the ELC (which traditionally took place in April), but it allows the conference to match with the Linaro Connect event for the first quarter of 2012.
The next Embedded Linux Conference Europe will take place on November 6-9 2012 in Barcelona, Spain. This is a just a ~4h drive from Toulouse, so definitely, several Bootlin people should be there.

Bootlin at Embedded Linux Conference Europe 2011

The next Embedded Linux Conference Europe will take place from October 26th to October 28th in Prague, together with the first edition of LinuxCon Europe and just after the Kernel Summit, the GStreamer conference and the Real-time Linux workshop: it’s a really impressive concentration of interesting talks for embedded Linux developers. Linus Torvalds is already announced as a keynote speaker of the LinuxCon Europe.

ELCE 2011

As ELCE is a conference that embedded Linux developers simply can’t miss, the complete team of Bootlin will be there: my colleague and Bootlin founder Michael Opdenacker (Michael is part of the organization committee for this event), my engineer colleagues Grégory Clément and Maxime Ripard and myself, Thomas Petazzoni.

I will also have the chance to give two talks during this edition of ELCE:

Using Buildroot for real products. As Bootlin has used and is using Buildroot for multiple customer projects, this talk will share our experience on how to configure and setup Buildroot properly to build embedded Linux systems and include in a clean and nice way all of the specificities of each product.
Using Qt for non-graphical applications. Qt is often seen only as a graphical library, but it is in fact much more than that. Based on the experience of a customer project, this presentation will detail all the nice features that Qt offers to build embedded applications.

We highly recommend this conference to European embedded Linux developers and hope to meet some of our readers there! We will be the guys behind the video cameras in the embedded rooms. It’s worth mentioning that ELCE attendees are also granted, for free, the right to access LinuxCon Europe talks.

The file and local site method