Late october will be a busy moment for all the embedded Linux developers meeting in Edinburgh, UK. The Linux Foundation is organizing a number of conferences here, including the Embedded Linux Conference Europe (October 24-25) and LinuxCon Europe (October 21-23), and many co-located other events.
Bootlin will be present at several of these events:
First, three Bootlin engineers will be present at the ARM kernel summit on October 22nd and 23rd. The ARM kernel summit is an invitation-only conference, organized in relation with the Linux Kernel Summit. Gregory Clement, Maxime Ripard and Thomas Petazzoni, engineers at Bootlin have been invited due to their participation to the ARM support in the kernel, mainly on Allwinner SOCs for Maxime and on Marvell SOCs for Gregory and Thomas. Being present at this event is an excellent opportunity to be part of the discussion that shapes the future of ARM support in Linux, and strengthen our relations with other members of this growing community.
Then, the entire technical team of Bootlin will attend the Embedded Linux Conference, on October 24th and 25th. Several talks will also be given by Bootlin engineers:
On Thursday, 24th October at 11:40 AM, Thomas Petazzoni will give a talk titled Device Tree for dummies!, which will give an introduction to the Device Tree on ARM: what it is, how it is compiled, how it used by the kernel, how Device Tree bindings are defined, how drivers are affected by the Device Tree, etc.
At the same time in another room, Michael Opdenacker will lead a Bird of a Feather session dedicated to Small Businesses in the embedded Linux world. Exchanging experiences, networking with other companies working in the same field, etc.
Still on Thursday, at 3 PM, Gregory Clement will give a talk on the Linux kernel Common Clock Framework, which will be an updated version of the talk he gave at ELC earlier this year.
On Saturday 26th and Sunday 27th October, the Buildroot community is organizing its traditional Developers Meeting, to which Thomas Petazzoni will participate. Some of the core Buildroot developers will join for two days of discussion and work to improve this embedded Linux build system.
As you can see, this will be a very interesting and busy week, and we’re all looking forward to meeting more embedded Linux developers and learning about the latest technologies in this field.
The 2013.08 release of Buildroot has been published a few days ago by Peter Korsgaard, the project maintainer. As usual, this release contains a number of improvements and new features that are summarized in Peter’s release e-mail, and also visible in the CHANGES file.
On a total of 744 commits merged for this release, Bootlin has contributed 141 patches, focusing on the following main improvements:
Conversion of the “internal toolchain back-end” of Buildroot to use the package infrastructure. The internal toolchain back-end is the piece of code in Buildroot that is responsible for building a cross-compilation toolchain (i.e building binutils, gcc, the C library, gdb and the necessary dependencies). Until now, this code was using some basic makefiles, many of which dating from many years back in the history of Buildroot. By converting this piece of code to use normal Buildroot packages, it is now easier to maintain and extend. It is worth noting that the internal toolchain back-end is only one of the two back-ends of Buildroot in terms of toolchains: it can also use pre-built external toolchains.
Thanks to the clean up highlighted above, we have added eglibc support to the internal toolchain back-end. Until now, using eglibc or glibc was only possible using pre-built external toolchains. Now, Buildroot is directly capable of building eglibc-based toolchains, in addition to the uClibc library which has been supported for many years by Buildroot. Note that we have already posted patches that also add glibc support, they should hopefully be included for the next release, 2013.11.
Vast improvements in the way Buildroot supports the various floating point possibilities on ARM: we’ve added support for the EABIhf ABI, improved how the various floating point units can be selected, etc. Selecting the right floating point solution for your embedded Linux system should now be a lot easier.
Support to build a system using the Thumb2 instruction set available on ARM, which provides a smaller code size compared to the classical ARM instruction set.
Updates to the available external toolchains: addition of the Arago ARMv5 and ARMv7 toolchains, and update the versions of the available Linaro toolchains for ARM and AArch64.
Addition of packages to support the video decoding hardware of some AT91 SoCs, the Hantro x170.
Moreover, in the absence of the official maintainer Peter Korsgaard, Thomas Petazzoni has played the role of interim maintainer during approximately one month, and has handled the first two release candidates of the 2013.08 cycle.
Last but not least, Thomas has also been the mentor of Spenser Gilliland, a student working on Buildroot as part of the Google Summer of Code. His work consists in improving support for ARM multimedia features in Buildroot, and a part of his work went into the 2013.08 release:
Addition of a libvpx package
Addition of a libopenmax virtual package to support various OpenMAX implementations
A complete bump of the Glib/Gtk stack
The addition of GStreamer 1.x support (Buildroot already had support for GStreamer 0.10.x, but not the more recent 1.x)
Addition of the gst-omx package which allows accelerated video decoding on the Raspberry Pi board thanks to an OpenMAX specific implementation
Addition of a ti-gfx package that allows to support OpenGL on TI OMAP platforms, it has been successfully tested with the BeagleBoard XM
Addition of the sunxi-mali package to support OpenGL on Allwinner SOCs, and the sunxi-cedarx package to support accelerated video decoding on Allwinner SOCs
The Google Summer of Code is still on-going until the end of September, and Spenser has already posted patches to improve support for Mesa3D, libdrm and the addition of the glmark2 OpenGL benchmark. Those improvements will hopefully be part of the next 2013.11 release.
In detail, the contributions from Bootlin for this release have been:
The Buildroot project is participating for the first time to the famous Google Summer of Code. This program, operated by Google, allows open-source projects to have students working on specific tasks for the summer, and the students get paid for their work, get mentored by open-source developers, learn about software development, open-source communities and more.
For its first participation to the GSoC, the Buildroot community has chosen one project: improving support for multimedia features of popular ARM SoCs. This consists in packaging in Buildroot all the necessary libraries and software components to support OpenGL, OpenVG, EGL, OpenMAX and similar technologies for the major ARM processors. The selected student for this project is Spenser Gilliland and Bootlin engineer Thomas Petazzoni is mentoring Spenser for this project.
The focus of the project is to add support for the multimedia features of the OMAP3, OMAP4 and AM33xx processors from Texas Instruments, the Broadcom processor found on the RasberryPi, the i.MX6 processor from Freescale, the Exynos 4 from Samsung and the Allwinner A1x processors. Throughout the next three months, support for the multimedia capabilities of those processors in Buildroot should become easier to use.
Spenser has already contributed support for GStreamer 1.x in Buildroot (which required upgrading the entire GLib/Gtk/Webkit stack) and OpenMAX support for the RasberryPi, and he is currently working on OpenGL support for the OMAP3/OMAP4/AM33xx platforms. The initial part of Spenser’s work will be in the next 2013.08 Buildroot release, while the remainder will have to wait the 2013.11 release.
As planned by the release schedule, the Buildroot 2013.05 version landed at the end of May. Peter Korsgaard, the project’s maintainer, highlighted the most important additions in his release email. With more than 900 commits, it has been the busiest ever development cycle, showing that the Buildroot project is more and more active.
With 175 commits in this release, Bootlin has again participated significantly to the development of Buildroot:
217 Gustavo Zacarias
167 Thomas Petazzoni (Bootlin)
109 Will Wagner
86 Peter Korsgaard
44 Simon Dawson
27 Yann E. MORIN
25 gilles.talis@gmail.com
[...]
6 Maxime Ripard (Bootlin)
[...]
1 Alexandre Belloni (Bootlin)
1 Ezequiel Garcia (Bootlin)
[...]
Amongst the features and improvements contributed by Bootlin:
Support for the next generation Wayland display server has been added. For now, only Wayland over the framebuffer is supported, but additional improvements are expected to come in the future.
Integration of packages to build all the Qt5 components: qt5base, qt5declarative, qt5graphicaleffects, qt5imageformats, qt5jsbackends, qt5multimedia, qt5quick1, qt5script, qt5svg, qt5webkit and qt5xmlpatterns.
A mechanism of virtual packages to expose the OpenGL, OpenVG and EGL implementations has been put in place, with for now the RasberryPi providing such implementations. Those virtual packages are for example used in the Qt5 packages mentionned above, for those that require OpenGL.
A cleanup of Buildroot core dependencies: flex and bison are no longer mandatory to use Buildroot, they are automatically built when needed. This apparently simple move required a number of fixes and updated to a significant number of packages.
Many external toolchains were updated, especially the Linaro toolchains.
The build process of gdb was converted to the package infrastructure, instead of being a hand-written Makefile. This is part of an effort to progressively convert the toolchain building process to the package infrastructure.
A default configuration was added for the Atmel AT91SAM9G45M10-EK evaluation board, which allows Buildroot users to easily build a minimal working system for this platform.
A number of build issues were fixed by Maxime Ripard, thanks to the daily automated builds done by the Bootlin Jenkins system that Maxime has set up.
A huge number of build issues trigerred by the autobuilders have also been fixed thanks to Bootlin engineers contributions.
For about 6 months, we’ve been working with Crystalfontz America on an imx28-based board, targeted at the hackers and DIYers. We’ve been working on the BSP, adding support to Linux and in Buildroot for this board. Support in the mainline Linux kernel is also in pretty good shape, and we continue to post patches to improve it.
The CFA-10036 is actually a computer-on-module with a small OLED display, and comes with two (for now) breakout boards, the CFA-10037, which adds USB and Ethernet connectivity, and an awful lot of exposed GPIOs, and the soon-to-be announced CFA-10049, which is more targeted to industrial or robotic uses, with additional ADCs, fan controller, 1-wire, LCD, rotary encoder, and so on. See more details.
The project is getting close to completion, since Crystalfontz started its funding campaign on Kickstarter.
For those who are not familiar with Kickstarter, it’s a way for creators to get funding and sense customer interest in their projects. If you find the device interesting you can either make a small pledge to show that you like the project, or make a bigger one and will receive board(s) and accessories corresponding to how much you pledged. If the project doesn’t meet its funding goals, you won’t be charged at all. I advise you to read the Kickstarter FAQ to understand Kickstarter better.
In a previous post, we detailed all the talks of the Embedded Systems and Open Hardware track of the Libre Software Meeting, taking place in Geneva in early July.
Bootlin will have a quite important presence at this event, with three talks and one tutorial given by Bootlin engineers. You’ll find below the descriptions of the talks given by Bootlin. Both my colleague Maxime Ripard and myself will be present at Libre Software Meeting, and we will be happy to meet you there to discuss Embedded Linux and Android topics!
A look through the Android Stack
Android has established itself in the past years as a major player in the mobile market, outperforming any other mobile systems.
To do so, Google relied both on well established open-source components, such as the Linux Kernel, and munching them together in a brand new userspace environment. This talk will detail the most important components of Android userspace and the interactions between them that allow developers to face a consistent API for their applications.
This talk will be given on Tuesday 9th July 2012, at 14:00, by Maxime Ripard, embedded Linux and Android engineer at Bootlin. Maxime is also teaching our newest training course on Android system development.
Buildroot: a nice, simple and efficient embedded Linux build system
Started in late 2001 by uClibc developers, Buildroot has grown over its 10 years history from a testing tool for the uClibc C library to a complete, vendor-neutral, embedded Linux build system. Until early 2009, the project was mostly unmaintained and the quality slowly decreased, frustrating many Buildroot users. Fortunately, since early 2009, Peter Korsgaard took over the maintainership of Buildroot, and the project has considerably evolved since then: stable releases are published every three months, the user and developer community has grown significantly, the existing features have been cleaned up, many other new features have been added, the project is no longer uClibc-specific and the quality has been vastly improved. Buildroot now offers a nice, simple and efficient mechanism to build small to medium sized embedded Linux systems, such as the ones found in many industrial systems or highly dedicated systems. Many users are amazed about how easy it is to get started with Buildroot, especially compared to other build systems. This presentation will show how Buildroot can be used to build embedded Linux systems, highlighting the new features and improvements made over the last few years, and detailing how the simplicity of Buildroot allows you to focus on developing the applications for your system. A quick overview of the future Buildroot developments will also be provided.
This talk will take place on Wednesday 10th July at 17:00 and will be given by Thomas Petazzoni, embedded Linux engineer at Bootlin, and long time Buildroot contributor.
Linux kernel on ARM: consolidation work
In Spring 2011, Linus Torvalds asked the ARM Linux maintainers to clean up the contents of arch/arm/ in the Linux kernel code by doing more consolidation between ARM sub-architectures.
More than a year later, a lot of work has been accomplished in this area, especially thanks to the introduction of the device tree for the ARM architecture, the pinctrl subsystem and the clock framework into the Linux kernel.
Through this talk, we will present the challenges the ARM architecture creates in terms of Linux kernel support, and then describe from a technical point of view how the device tree, the pinctrl subsystem and the clock subsystem work and how they can improve the consolidation between different ARM sub-architectures.
The talk will be designed to be accessible to an audience having only a moderate knowledge of kernel programming and internals, and will therefore provide enough context for such audience to understand the issues that those different mechanisms are striving to solve.
This talk will take place on Thursday 11th July at 10:00 and will be given by Thomas Petazzoni, embedded Linux engineer at Bootlin.
Tutorial on using Buildroot, a nice, simple and efficient embedded Linux build system
Started in late 2001 by uClibc developers, Buildroot has grown over its 10 years history from a testing tool for the uClibc C library to a complete, vendor-neutral, embedded Linux build system. Until early 2009, the project was mostly unmaintained and the quality slowly decreased, frustrating many Buildroot users. Fortunately, since early 2009, Peter Korsgaard took over the maintainership of Buildroot, and the project has considerably evolved since then: stable releases are published every three months, the user and developer community has grown significantly, the existing features have been cleaned up, many other new features have been added, the project is no longer uClibc-specific and the quality has been vastly improved. Buildroot now offers a nice, simple and efficient mechanism to build small to medium sized embedded Linux systems, such as the ones found in many industrial systems or highly dedicated systems. Many users are amazed about how easy it is to get started with Buildroot, especially compared to other build systems.
This workshop follows the Buildroot presentation proposed in the same topic. During one half-day participants will be introduced on how to efficiently use Buildroot for their own projects:
Basic usage of Buildroot: generate the first system, boot it on a hardware platform
Add packages to Buildroot
Customize Buildroot for real-life projects: how to integrate project specific patches, configuration and customization
Participants are invited to come with their own laptop, installed with a sufficiently recent GNU/Linux distribution. Participants are recommended to attend the Buildroot talk by the same speaker before attending the workshop, as the talk will give an overall introduction on Buildroot.
This tutorial will take place on Thursday 11th July from 14:00 to 17:00 and will be given by Thomas Petazzoni, embedded Linux engineer at Bootlin, and long time Buildroot contributor.
The Libre Software Meeting is a community-driven free software event that exists since 2000, composed of talks and workshops. Its 2012 edition will take place from July 7th to July 12th in Geneva, Switzerland.
In the context of this conference, I was responsible with Florian Fainelli from the OpenWRT project to organize the Embedded systems and open hardware track. This track will offer an interesting selection of talks related to embedded topics, concentrated between July 9th and July 11th:
Make a free camera fly with free hardware, Éric Boudrand. It will be the only talk of the track that will take place in French. The rest of the track contents will be in English.
I recently had the opportunity to use Yocto. I already practiced quite a lot with OpenEmbedded before. You can see Yocto as a project derived from OpenEmbedded even it is a bit more than that.
In fact, Yocto is made of Poky (a build system based on OpenEmbedded), a few added build tools (swabber, pseudo, etc.), as well as a set of meta data allowing to create embedded distributions for a number of targets.
The strength but also the weakness of OpenEmbedded is that it a very flexible build system. It can make production root filesystems, but also a complete distribution with its ready to use package repository, and this for multiple hardware platforms. It makes it a difficult system to get started and get efficient with. Even two years ago, the OpenEmbedded documentation contributed to making it difficult to get started. Indeed, OpenEmbedded did supply some documentation, but which only started to make sense once you start mastering it. This is quite a paradox for a piece of documentation. It lacked the elements allowing developers to understand its operation well.
With Yocto, I was pleased to realize that substantial progress had been made on this side. The project comes with documentation that is much more exhaustive and above all much more accessible for beginners. Getting started with it is still not completely straightforward, but this time, this is rather because of the complexity and the rich features of the tool.
In a few hours, I managed to develop a minimalistic BSP (Board Support Package) for a given board (in this case a AT91SAM9G20-EK). The concept of layer allows to have a configuration layer specific to a given piece of hardware. You can even support multiple hardware platforms at once and add specific packages. A layer is indeed just a set of packages and configurations (or configuration overrides). The BSP is just a layer specific to one or several pieces of hardware.
As you can see, even to support a simple embedded board, there is already a number of concepts to deal with. There are also multiple ways of achieving the same result but which will be easier or more difficult to maintain. The concept of “BSP” for Yocto is therefore a kind of guideline to allow the Yocto community to have a common point of reference. I will try to illustrate the use of a BSP on the AT91SAMG20-EK board here and/or on my Google+ page.
Another significant progress is optimizing build time for a “minimalistic” target, which went down from more than three hours to just over one hour now. It remains a long time for a very simple target.
To build a filesystem image with only a few components, Buildroot remains much more appropriate. For systems that require a great number of components, more advanced functionality is then often needed, such as managing a package repository and supporting multiple hardware platforms at once for example. In this case, Yocto remains the best (the only?) option, all the more as this project addresses the traditional weaknesses of OpenEmbedded.
It’s now Thursday morning here in Redwood City, California, and I didn’t had the time yesterday morning to do a write-up about our second day at the Android Builders Summit. Hopefully the following write-up will give our readers some details about what happened during this day.
This second of Android Builders Summit was co-located with the Yocto Developer Day, and as my colleagues Maxime Ripard and Grégory Clément were attending the two tracks of Android Builders Summit, I decided that I would attend the Yocto Developer Day.
Yocto Developer Day
Yocto is an umbrella project that consists in creating an embedded Linux build system, called Poky and some associated development tools. Poky takes its roots into the OpenEmbedded community: it re-uses the bitbake recipe processor, and a set of recipes for building packages that are now shared between Yocto and OpenEmbedded through the openembedded-core repository. At Bootlin, we are strong contributors to the Buildroot build system, and we use it for many of our customer projects. However, being pushed very strongly by Intel and the Linux Foundation, Yocto is gaining traction, and the fact that Yocto provides stable releases every 6 months now makes it a lot more usable than OpenEmbedded, which had to be checked out through Git, leaving the user with the uncertainty on whether the version (s)he got would actually work or not. And moreover, Buildroot and Yocto are not really competing projects: Buildroot is a simple root filesystem image generator, while Yocto is more a cross-distribution generator, they target projects of different sizes.
I started attending the Yocto Developer Day with a general presentation talk about what Yocto is and why it is necessary. Nothing really new in this talk for someone who already uses embedded Linux build systems and understands the need for such tools. However, the thing that always surprises me is that the Yocto project claims everywhere to solve the fragmentation problem in the embedded Linux build system space (there are too many tools in this area) by creating the tool, and that they envision that in 5 years, everybody will link embedded Linux build with the Yocto project. It’s quite funny because at the moment, they have just created yet another build system 🙂 But it’s true that the project is gaining traction and seems to attract the SoC vendors, which is a good thing because having a standard build system is so much better than having crappy vendor-specific build systems.
Yocto Developer Day: Yocto introduction by Saul Wold from Intel
The second talk, by Saul Wold, from Intel, went more into the details on how to use Yocto: what the different components are, how recipes are written, how configuration is defined, what tasks, images, recipes, etc are. I would have liked if the talk went a bit further into the details, but it gave a very good introduction to the Poky build system.
In the afternoon, I attended a hands-on session for new users to Yocto. The room setup was very impressive: about forty high-end PCs provided, each having a development board next to it. The first part of the hands-on session consisted in using Yocto to produce a basic filesystem image which we booted into Qemu. In order to solve the very long first build problem that all OpenEmbedded and Yocto users face, they had pre-built a number of packages and stored them into a shared state directory. Interestingly, the size of the Yocto output directory was about 30 GB, just to build an embedded Linux system with BusyBox and a few minor things. Once this was done, we went ahead in creating our own layer, in order to define our own image and its contents it terms of packages. We used it to add a graphical splashscreen, and I also extended it to include Dropbear into the build. The whole thing went quite well. One thing that worries me is that bitbake and the build process really looks like a black box, and it seems hard to understand what’s going on behind the scenes. With Buildroot, I am used to a very simple build system with which it is very easy to fully understand what’s going on. Here, even the people that give speeches about Yocto or deliver a bit of training, seem to not fully understand what’s going on. This impression is also validated by the complexity of the output directory (where all the build results are). But maybe it’s just a matter of spending some time using it and reading some code, but the fact that people that have been developing/using Yocto for a while still do not really understand its internals is a bit surprising. Or maybe it’s just a wrong impression on my side.
Yocto Developer Day: hands-on session starting
The next part of the hands-on was around the Eclipse integration of Yocto. First with ADT (Application Development Toolkit), which integrates the cross-development thing into Eclipse. Thanks to an agent running into the target, Eclipse is able to push the application binary to the target and start gdbserver on it, and therefore transparently start a debugging session for the user. I am not a big fan of Eclipse (I have been an Emacs user for a huge number of years), but it’s true that for people used to Integrated Development Environments, this ADT thing provides a quite nice experience. Then, we went ahead in trying to use HOB, which integrates into Eclipse the possibility of selecting which packages should be built and integrated into the image. Unfortunately, it seems it didn’t work for anybody (even though we were selecting the package in the GUI, it didn’t appear in the final filesystem image), but that wasn’t a big problem since I don’t really see the point in a tool such as HOB: editing configuration files is something that shouldn’t scare any embedded Linux developer.
Regardless of the contents of the hands-on, I was quite interested by how it was conducted. Instead of having some written lab instructions, and having everyone following, alone, those lab instructions, the instructor was simply demoing the various steps to be done on the video-projector screen, which we simply had to replicate. It makes the session quite interactive, with of course the drawback that everyone needs to progress at the same pace.
All in all, this Yocto Developer Day was interesting, and I hope to find some time soon to experiment further with Yocto.
Android Builders Summit
My colleagues attended multiple talks about Android during this second day of the conference. In the morning, they attended Headless Android, Towards a Standard Audio HAL for Android, Android on eMMC: Optimizing for Performance.
Android Builders Summit: Real-time Android
In the afternoon, Grégory attended the Real-Time Android talk, which he said, was interesting. It showed that it was possible to integrate the PREEMPT_RT patches together with the Android kernel modifications, and provide a system having real-time capabilities for native (C/C++) applications and still the nice aspect of the Android user interface. During the same slot, Maxime attended the Android Services Black Magic, given by Aleksandar (Saša) Gargenta from Marakana. As usual with the Gargenta brothers, the talk was highly interesting and gave a lot of detailed information about Android services.
Some other thoughts…
At the organization level, the conference organizers should make it clear in the conference program and flyer the location where the slides will be posted. At almost every talk there is someone that asked if and where the slides will be posted, and the speakers are sometimes a bit uncomfortable because there is no clearly identified place to post the slides. In the past years, it was made clear that the slides would be posted on the elinux.org wiki, but this year, things are very unclear. Moreover, it’s even more surprising since speakers are asked to post their slides into their Linux Foundation website account, but those slides are not being made visible. Maybe a good suggestion for the Linux Foundation would be to improve how slides are handled and posted online.
Another thought about the Android Builders Summit is the surprising absence of Google, the developer and maker of Android. Google sponsors the Embedded Linux Conference which takes place right after the Android Builders Summit, but they do not sponsor the Android Builders Summit. There is also no talk from Google developers, and I haven’t seen any Google person in the attendees. It’s even more surprising when we know that the conference takes place in a location about 18 minutes away by car from Google headquarters in Mountain View. Maybe Google doesn’t want to see Android being used in application areas other than phones and tablets?
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.
Android Builders Summit 2012
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.
Embedded Linux Conference 2012
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!
