12.1. |
How does Poky differ from OpenEmbedded? |
The term "Poky" refers to the specific reference build system that the Yocto Project provides. Poky is based on OE-Core and BitBake. Thus, the generic term used here for the build system is the "OpenEmbedded build system." Development in the Yocto Project using Poky is closely tied to OpenEmbedded, with changes always being merged to OE-Core or BitBake first before being pulled back into Poky. This practice benefits both projects immediately. |
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12.2. |
I only have Python 2.4 or 2.5 but BitBake requires Python 2.6 or 2.7. Can I still use the Yocto Project? |
You can use a stand-alone tarball to provide Python 2.6. You can find pre-built 32 and 64-bit versions of Python 2.6 at the following locations:
These tarballs are self-contained with all required libraries and should work on most Linux systems. To use the tarballs extract them into the root directory and run the appropriate command: $ export PATH=/opt/poky/sysroots/i586-pokysdk-linux/usr/bin/:$PATH $ export PATH=/opt/poky/sysroots/x86_64-pokysdk-linux/usr/bin/:$PATH
Once you run the command, BitBake uses Python 2.6. |
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12.3. |
How can you claim Poky / OpenEmbedded-Core is stable? |
There are three areas that help with stability;
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12.4. |
How do I get support for my board added to the Yocto Project? |
Support for an additional board is added by creating a Board Support Package (BSP) layer for it. For more information on how to create a BSP layer, see the "Understanding and Creating Layers" section in the Yocto Project Development Manual and the Yocto Project Board Support Package (BSP) Developer's Guide. Usually, if the board is not completely exotic, adding support in the Yocto Project is fairly straightforward. |
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12.5. |
Are there any products built using the OpenEmbedded build system? |
The software running on the Vernier LabQuest is built using the OpenEmbedded build system. See the Vernier LabQuest website for more information. There are a number of pre-production devices using the OpenEmbedded build system and the Yocto Project team announces them as soon as they are released. |
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12.6. |
What does the OpenEmbedded build system produce as output? |
Because you can use the same set of recipes to create output of various formats, the output of an OpenEmbedded build depends on how you start it. Usually, the output is a flashable image ready for the target device. |
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12.7. |
How do I add my package to the Yocto Project? |
To add a package, you need to create a BitBake recipe. For information on how to add a package, see the section "Writing a Recipe to Add a Package to Your Image" in the Yocto Project Development Manual. |
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12.8. |
Do I have to reflash my entire board with a new Yocto Project image when recompiling a package? |
The OpenEmbedded build system can build packages in various
formats such as IPK for OPKG, Debian package
( |
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12.9. |
What is GNOME Mobile and what is the difference between GNOME Mobile and GNOME? |
GNOME Mobile is a subset of the GNOME platform targeted at mobile and embedded devices. The the main difference between GNOME Mobile and standard GNOME is that desktop-orientated libraries have been removed, along with deprecated libraries, creating a much smaller footprint. |
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12.10. |
I see the error ' |
You are probably running the build on an NTFS filesystem.
Use |
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12.11. |
How do I make the Yocto Project work in RHEL/CentOS? |
To get the Yocto Project working under RHEL/CentOS 5.1 you need to first install some required packages. The standard CentOS packages needed are:
On top of these, you need the following external packages:
Once these packages are installed, the OpenEmbedded build system will be able
to build standard images.
However, there might be a problem with the QEMU emulator segfaulting.
You can either disable the generation of binary locales by setting
NoteFor information on distributions that the Yocto Project uses during validation, see the Distribution Support Wiki page. For notes about using the Yocto Project on a RHEL 4-based host, see the Building on RHEL4 Wiki page. |
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12.12. |
I see lots of 404 responses for files on
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Nothing is wrong. The OpenEmbedded build system checks any configured source mirrors before downloading from the upstream sources. The build system does this searching for both source archives and pre-checked out versions of SCM-managed software. These checks help in large installations because it can reduce load on the SCM servers themselves. The address above is one of the default mirrors configured into the build system. Consequently, if an upstream source disappears, the team can place sources there so builds continue to work. |
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12.13. |
I have machine-specific data in a package for one machine only but the package is being marked as machine-specific in all cases, how do I prevent this? |
Set |
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12.14. |
I'm behind a firewall and need to use a proxy server. How do I do that? |
Most source fetching by the OpenEmbedded build system is done by http_proxy = http://proxy.yoyodyne.com:18023/ ftp_proxy = http://proxy.yoyodyne.com:18023/
The Yocto Project also includes a
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12.15. |
What’s the difference between |
The |
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12.16. |
I'm seeing random build failures. Help?! |
If the same build is failing in totally different and random ways, the most likely explanation is:
The OpenEmbedded build system processes a massive amount of data that causes lots of network, disk and CPU activity and is sensitive to even single-bit failures in any of these areas. True random failures have always been traced back to hardware or virtualization issues. |
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12.17. |
What do we need to ship for license compliance? |
This is a difficult question and you need to consult your lawyer for the answer for your specific case. It is worth bearing in mind that for GPL compliance, there needs to be enough information shipped to allow someone else to rebuild and produce the same end result you are shipping. This means sharing the source code, any patches applied to it, and also any configuration information about how that package was configured and built. You can find more information on licensing in the "Licensing" and "Maintaining Open Source License Compliance During Your Product's Lifecycle" sections, both of which are in the Yocto Project Development Manual. |
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12.18. |
How do I disable the cursor on my touchscreen device? |
You need to create a form factor file as described in the
"Miscellaneous Recipe Files"
section in the Yocto Project Board Support Packages (BSP)
Developer's Guide.
Set the HAVE_TOUCHSCREEN=1
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12.19. |
How do I make sure connected network interfaces are brought up by default? |
The default interfaces file provided by the netbase recipe does not automatically bring up network interfaces. Therefore, you will need to add a BSP-specific netbase that includes an interfaces file. See the "Miscellaneous Recipe Files" section in the Yocto Project Board Support Packages (BSP) Developer's Guide for information on creating these types of miscellaneous recipe files. For example, add the following files to your layer: meta-MACHINE/recipes-bsp/netbase/netbase/MACHINE/interfaces meta-MACHINE/recipes-bsp/netbase/netbase_5.0.bbappend
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12.20. |
How do I create images with more free space? |
By default, the OpenEmbedded build system creates images that are 1.3 times the size of the populated root filesystem. To affect the image size, you need to set various configurations:
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12.21. |
Why don't you support directories with spaces in the pathnames? |
The Yocto Project team has tried to do this before but too
many of the tools the OpenEmbedded build system depends on,
such as |
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12.22. |
How do I use an external toolchain? |
The toolchain configuration is very flexible and customizable.
It is primarily controlled with the
The default value of
In addition to the toolchain configuration, you also need a
corresponding toolchain recipe file.
This recipe file needs to package up any pre-built objects in
the toolchain such as For information on installing and using cross-development toolchains, see the "Installing the ADT and Toolchains" section in the Yocto Project Application Developer's Guide. |
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12.23. |
How does the OpenEmbedded build system obtain source code and will it work behind my firewall or proxy server? |
The way the build system obtains source code is highly configurable. You can setup the build system to get source code in most environments if HTTP transport is available.
When the build system searches for source code, it first
tries the local download directory.
If that location fails, Poky tries
Assuming your distribution is "poky", the OpenEmbedded build
system uses the Yocto Project source
As an example, you could add a specific server for the
build system to attempt before any others by adding something
like the following to the PREMIRRORS_prepend = "\ git://.*/.* http://www.yoctoproject.org/sources/ \n \ ftp://.*/.* http://www.yoctoproject.org/sources/ \n \ http://.*/.* http://www.yoctoproject.org/sources/ \n \ https://.*/.* http://www.yoctoproject.org/sources/ \n"
These changes cause the build system to intercept Git, FTP,
HTTP, and HTTPS requests and direct them to the
Aside from the previous technique, these options also exist: BB_NO_NETWORK = "1" This statement tells BitBake to issue an error instead of trying to access the Internet. This technique is useful if you want to ensure code builds only from local sources. Here is another technique: BB_FETCH_PREMIRRORONLY = "1"
This statement limits the build system to pulling source
from the Here is another technique: BB_GENERATE_MIRROR_TARBALLS = "1" This statement tells the build system to generate mirror tarballs. This technique is useful if you want to create a mirror server. If not, however, the technique can simply waste time during the build.
Finally, consider an example where you are behind an
HTTP-only firewall.
You could make the following changes to the
PREMIRRORS_prepend = "\ ftp://.*/.* http://www.yoctoproject.org/sources/ \n \ http://.*/.* http://www.yoctoproject.org/sources/ \n \ https://.*/.* http://www.yoctoproject.org/sources/ \n" BB_FETCH_PREMIRRORONLY = "1"
These changes would cause the build system to successfully
fetch source over HTTP and any network accesses to anything
other than the
The build system also honors the standard shell environment
variables |
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12.24. |
Can I get rid of build output so I can start over? |
Yes - you can easily do this.
When you use BitBake to build an image, all the build output
goes into the directory created when you source the
Within the Build Directory, is the |