The Linux kernel backports project aims at backporting Linux upstream device drivers for usage on older kernels. The point of the project is to provide a central mechanism for backporting device drivers for any subsystem and enable both users and developers to always focus on upstream Linux kernel development. The backports project shall never include proprietary drivers and by design does not allow usage of itself with proprietary drivers. Every backports release has been test compiled for usage against all supported kernels, currently 2.6.24 - latest. Note that Linux kernel releases can become deprecated. Right now we provide backport support for all kernels 2.6.24 up to the latest release inclusive even if a kernel is deprecated however you are encouraged to follow the best practices and at the very least be on a supported Linux kernel. Supported stable kernels are annotated on kernel.org.
Both daily snapshots based on linux-next, and stable releases based 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 you may be on from 2.6.24 - 3.(x-1).
Currently backported subsystems
Device drivers are available for the following subsystems:
* Ethernet * Wireless * Bluetooth * NFC * ieee802154 (will be available on v3.11 releases) * GPU * Media * Regulator
Whether or not a device driver is available from a subsytem will depend on whether or not a developer decided to backport it and if the device driver is backported down to the kernel you are on. Device drivers available on a release will be available and displayed on the backports configuration, through make menuconfig. If you see the driver on make menuconfig it means you can use it. An alternative is to look at the git tree dependencies file. Note that the dependencies does not exist on a release, it only exist on the development git tree. Someone is welcome to come up with a fancy page that provides the device driver <--> kernel dependency map page. If a device driver is available on make menuconfig but is not listed on the dependencies file it means it is available for usage on all supported kernel, v2.6.24 - on.
Building backports follows the same build mechanism as building the Linux kernel.
# as a user make menuconfig make -j4 # as root make install # reboot and enjoy
Its understood users may not 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.
make help make defconfig-help
If you use this option just use the 'make defconf-option' in replacement for make menuconfig above. For example to compile all DRM drivers:
# as a user make defconfig-drm make -j4 # as root make install
Note that there are only default configuration files written for a few drivers while the project actually backports over 830 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).
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