From ed0a240e1632682ec4c33341f3e24ad71773cdfc Mon Sep 17 00:00:00 2001 From: Scott Rifenbark Date: Tue, 11 Dec 2012 12:07:58 -0600 Subject: documentation: Rename of poky-ref-manual folder to ref-manual. Changing the folder that holds the YP Reference Manual to be "ref-manual". This will help with confustion over the manual's intended purpose. (From yocto-docs rev: 1106442964b5080cb0b6b3bd3af32e9407c0f7c1) Signed-off-by: Scott Rifenbark Signed-off-by: Richard Purdie --- documentation/ref-manual/faq.xml | 606 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 606 insertions(+) create mode 100644 documentation/ref-manual/faq.xml (limited to 'documentation/ref-manual/faq.xml') diff --git a/documentation/ref-manual/faq.xml b/documentation/ref-manual/faq.xml new file mode 100644 index 0000000..176573d --- /dev/null +++ b/documentation/ref-manual/faq.xml @@ -0,0 +1,606 @@ + %poky; ] > + + +FAQ + + + + + 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. + For a fuller description of the term "Poky", see the + poky term in the Yocto Project + Development Manual. + + + + + + + + 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: + + 32-bit tarball + 64-bit tarball + + + + 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. + + + + + + + + How can you claim Poky / OpenEmbedded-Core is stable? + + + + + There are three areas that help with stability; + + The Yocto Project team keeps + OE-Core small + and focused, containing around 830 recipes as opposed to the thousands + available in other OpenEmbedded community layers. + Keeping it small makes it easy to test and maintain. + The Yocto Project team runs manual and automated tests + using a small, fixed set of reference hardware as well as emulated + targets. + The Yocto Project uses an an autobuilder, + which provides continuous build and integration tests. + + + + + + + + + How do I get support for my board added to the Yocto Project? + + + + + Support for an additional board is added by creating a BSP layer for it. + For more information on how to create a BSP layer, see 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. + + + + + + + + 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. + + + + + + + + What does the OpenEmbedded build system produce as output? + + + + + Because the same set of recipes can be used to create output of various formats, the + output of an OpenEmbedded build depends on how it was started. + Usually, the output is a flashable image ready for the target device. + + + + + + + + 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 + "Adding a Package" + in the Yocto Project Development Manual. + + + + + + + + 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 (.deb), or RPM. + The packages can then be upgraded using the package tools on the device, much like + on a desktop distribution such as Ubuntu or Fedora. + + + + + + + + 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. + + + + + + + + I see the error 'chmod: XXXXX new permissions are r-xrwxrwx, not r-xr-xr-x'. + What is wrong? + + + + + You are probably running the build on an NTFS filesystem. + Use ext2, ext3, or ext4 instead. + + + + + + + + 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: + + "Development tools" (selected during installation) + texi2html + compat-gcc-34 + + On top of these, you need the following external packages: + + python-sqlite2 from + DAG repository + + help2man from + Karan repository + + + + + 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 + ENABLE_BINARY_LOCALE_GENERATION + to "0" or by removing the linux-2.6-execshield.patch + from the kernel and rebuilding it since that is the patch that causes the problems with QEMU. + + + + + + + + I see lots of 404 responses for files on + http://www.yoctoproject.org/sources/*. Is something wrong? + + + + + 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. + + + + + + + + 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 SRC_URI_OVERRIDES_PACKAGE_ARCH + = "0" in the .bb file but make sure the package is + manually marked as + machine-specific in the case that needs it. + The code that handles SRC_URI_OVERRIDES_PACKAGE_ARCH is in base.bbclass. + + + + + + + + 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 wget + and you therefore need to specify the proxy settings in a + .wgetrc file in your home directory. + Example settings in that file would be + + http_proxy = http://proxy.yoyodyne.com:18023/ + ftp_proxy = http://proxy.yoyodyne.com:18023/ + + The Yocto Project also includes a site.conf.sample + file that shows how to configure CVS and Git proxy servers + if needed. + + + + + + + + What’s the difference between foo and foo-native? + + + + + The *-native targets are designed to run on the system + being used for the build. + These are usually tools that are needed to assist the build in some way such as + quilt-native, which is used to apply patches. + The non-native version is the one that runs on the target device. + + + + + + + + I'm seeing random build failures. Help?! + + + + + If the same build is failing in totally different and random ways, + the most likely explanation is that either the hardware you're running the + build on has some problem, or, if you are running the build under virtualisation, + the virtualisation probably has bugs. + The OpenEmbedded build system processes a massive amount of data causing 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 virtualisation issues. + + + + + + + + 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 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. + + + + + + + + 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 and set the HAVE_TOUCHSCREEN variable equal to one as follows: + + HAVE_TOUCHSCREEN=1 + + + + + + + + + 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 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 + + + + + + + + + How do I create images with more free space? + + + + + Images are created to be 1.2 times the size of the populated root filesystem. + To modify this ratio so that there is more free space available, you need to + set the configuration value IMAGE_OVERHEAD_FACTOR. + For example, setting IMAGE_OVERHEAD_FACTOR to 1.5 sets + the image size ratio to one and a half times the size of the populated + root filesystem. + + IMAGE_OVERHEAD_FACTOR = "1.5" + + + + + + + + + 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 autoconf + break when they find spaces in pathnames. + Until that situation changes, the team will not support spaces in pathnames. + + + + + + + + How do I use an external toolchain? + + + + + The toolchain configuration is very flexible and customizable. + It is primarily controlled with the + TCMODE variable. + This variable controls which tcmode-*.inc file to include + from the meta/conf/distro/include directory within the + source directory. + + + + The default value of TCMODE is "default" + (i.e. tcmode-default.inc). + However, other patterns are accepted. + In particular, "external-*" refers to external toolchains of which there are some + basic examples included in the OpenEmbedded Core (meta). + You can use your own custom toolchain definition in your own layer + (or as defined in the local.conf file) at the location + conf/distro/include/tcmode-*.inc. + + + + 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 + libgcc, libstdcc++, + any locales, and libc. + An example is the external-sourcery-toolchain.bb, which is located + in meta/recipes-core/meta/ within the source directory. + + + + + + + + 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 PREMIRRORS, the upstream source, + and then MIRRORS in that order. + + + By default, the OpenEmbedded build system uses the Yocto Project source PREMIRRORS + for SCM-based sources, + upstreams for normal tarballs, and then falls back to a number of other mirrors + including the Yocto Project source mirror if those fail. + + + As an example, you could add a specific server for Poky to attempt before any + others by adding something like the following to the local.conf + configuration file: + + 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 Poky to intercept Git, FTP, HTTP, and HTTPS + requests and direct them to the http:// sources mirror. + You can use file:// URLs to point to local directories + or network shares as well. + + + Aside from the previous technique, these options also exist: + + BB_NO_NETWORK = "1" + + This statement tells BitBake to throw 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 Poky to pulling source from the PREMIRRORS only. + Again, this technique is useful for reproducing builds. + + + Here is another technique: + + BB_GENERATE_MIRROR_TARBALLS = "1" + + This statement tells Poky 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 local.conf + configuration file as long as the PREMIRROR server is up to date: + + 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 Poky to successfully fetch source over HTTP and + any network accesses to anything other than the PREMIRROR would fail. + + + The build system also honors the standard shell environment variables + http_proxy, ftp_proxy, + https_proxy, and all_proxy + to redirect requests through proxy servers. + + + + + + + + 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 oe-init-build-env + setup file. + By default, this build directory + is named build but can be named + anything you want. + + + + Within the build directory is the tmp directory. + To remove all the build output yet preserve any source code or downloaded files + from previous builds, simply remove the tmp directory. + + + + + + + + -- cgit v1.1