kumquat-buildroot/package/linux-backports/Config.in
Petr Vorel 538898d5ed package/linux-backports: new package
Backports provide drivers released on newer kernels backported for usage
on older kernels.

There are two versions of linux-backports: one that supports Linux
kernels >= 3.0 and one supports even older kernels. We're only packaging
the version that supports >= 3.0.

linux-backports needs to have access to the kernel's .config to extract
information it reintroduces as blind options in generated Kconfig
snippets for its own menuconfig. However, Buildroot offers no way to
express this kind of dependency.

So we need to hand-write a dependency from linux-backports' own .config
to linux' .config .

Since linux.mk has not already been sourced by the time we source
linux-backports.mk, we are missing the definition for LINUX_DIR, so we
can not use it our rule.

Fortunately, make provides so-called "secondary expansion", by which
rules which dependencies include a $$-dereferenced variable wil lbe
re-evaluated after all the rest of the Makefiles have been parsed.

So, we use that secondary expansion to post-pone evaluation of that
dependency so we can use LINUX_DIR.

Note: reconstructing LINUX_DIR by hand does not work, because of the
custom archives, git tree, or override-srcdir.

Signed-off-by: Petr Vorel <petr.vorel@gmail.com>
Cc: Arnout Vandecappelle <arnout@mind.be>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
Reviewed-by: Romain Naour <romain.naour@openwide.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
2015-07-26 15:40:11 +02:00

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comment "linux-backports needs a Linux kernel to be built"
depends on !BR2_LINUX_KERNEL
config BR2_PACKAGE_LINUX_BACKPORTS
bool "linux-backports"
depends on BR2_LINUX_KERNEL
help
The linux-backports package includes many Linux drivers from
recent kernels, backported to older ones.
This version of linux-backports supports kernels starting from 3.0.
https://backports.wiki.kernel.org
if BR2_PACKAGE_LINUX_BACKPORTS
choice
prompt "Linux kernel driver backports configuration"
default BR2_PACKAGE_LINUX_BACKPORTS_USE_DEFCONFIG
config BR2_PACKAGE_LINUX_BACKPORTS_USE_DEFCONFIG
bool "Using an in-tree defconfig file"
config BR2_PACKAGE_LINUX_BACKPORTS_USE_CUSTOM_CONFIG
bool "Using a custom (def)config file"
endchoice
config BR2_PACKAGE_LINUX_BACKPORTS_DEFCONFIG
string "Defconfig name"
depends on BR2_PACKAGE_LINUX_BACKPORTS_USE_DEFCONFIG
help
Name of the backports defconfig file to use, without the
leading defconfig-. The defconfig is located in defconfigs/
directory in the backports tree.
config BR2_PACKAGE_LINUX_BACKPORTS_CUSTOM_CONFIG_FILE
string "Configuration file path"
depends on BR2_PACKAGE_LINUX_BACKPORTS_USE_CUSTOM_CONFIG
help
Path to the backports configuration file
Note: this can be a defconfig file or a complete .config file,
which can later be saved back with make linux-update-(def)config.
config BR2_PACKAGE_LINUX_BACKPORTS_CONFIG_FRAGMENT_FILES
string "Additional configuration fragment files"
help
A space-separated list of configuration fragment files, that
will be merged to the main linux-backports configuration file.
endif # BR2_PACKAGE_LINUX_BACKPORTS