+---

+title: Documentation/packaging

+---

+

+

+The backports project makes release of two types of '''packages''' which provides device drivers from future versions of Linux usable on older Linux kernel releases.

+

+<h2>Release types</h2>

+

+Both daily snapshots based on [http://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git linux-next], and stable releases based [http://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git Linux's stable releases] are provided. Always use the latest ''stable'' available release unless you need a feature / fix only currently available on the linux-next based release. A backports-3.x release means device drivers from the Linux v3.x release have been taken, backported and made available for you to use on any kernel version prior to the release version.

+

+<h2>Usage guide</h2>

+

+Building backports follows the same build mechanism as building the Linux kernel.

+

+<pre>

+# as a user

+make menuconfig

+make -j4

+# as root

+make install

+# reboot and enjoy

+</pre>

+

+Its understood users may not know how to configure the backports package, just like they may not know how to configure the Linux kernel, so a short cut is provided with default configuration files that can be used to only build their drivers / subsystems of interest. You can also just query the regular help menu.

+

+<pre>

+make help

+make defconfig-help

+</pre>

+

+If you use this option just use the 'make defconf-option' in replacement for ''make menuconfig'' above. For example to compile all wifi drivers:

+

+<pre>

+# as a user

+make defconfig-wifi

+make -j4

+# as root

+make install

+</pre>

+

+Note that there are only default configuration files written for a few drivers while the project actually backports a lot of device drivers, the reason we have default configuration files for a few drivers is simply because developer have provided a default config options for them. What we really need is a 'make localmodconfig' support but that will take a while given that it involves mapping older kernel configs to newer kernel configs (which likely would be welcomed upstream as well).

+

+<h2>Cross compiling</h2>

+

+To cross compile:

+

+ set -a

+ CROSS_COMPILE=${CROSS_COMPILE}

+ ARCH=${TARGET_CPU}

+ KLIB_BUILD=${DEV_PATH}/${LINUX_DIR}

+ KLIB=${TARGET_ROOT_ON_HOST}

+ set +a

+ make oldconfig # menuconfig worked here too

+ make

+ make install

+

+The 'make install' target isn't currently sane for cross-builds due to the bacport_firmware_install script not respecting prefixes. For now you can comment out that script few others like initrd updates, from being run out of the Makefiles.

+

+<h2>Cross compile with Freescale's LTIB</h2>

+

+To get backports happy in LTIB, use UNSPOOF/SPOOF_PATH to switch between host and cross environment. Example <i>Build</i> section in backports.spec

+

+ %Build

+ export PATH=$UNSPOOF_PATH

+

+ make menuconfig prefix=%{_prefix} \

+ CROSS_COMPILE=${TOOLCHAIN_PATH}/bin/${TOOLCHAIN_PREFIX} \

+ ARCH=$LINTARCH KLIB=${TOP}/rootfs/lib/modules/%{kversion} \

+ KLIB_BUILD=${TOP}/rpm/BUILD/linux

+

+ export PATH=$SPOOF_PATH

+

+ make prefix=%{_prefix} \

+ CROSS_COMPILE=${TOOLCHAIN_PATH}/bin/${TOOLCHAIN_PREFIX} \

+ ARCH=$LINTARCH KLIB=${TOP}/rootfs/lib/modules/%{kversion} \

+ KLIB_BUILD=${TOP}/rpm/BUILD/linux \ No newline at end of file