Added linux drivers backports project

https://backports.wiki.kernel.org

Signed-off-by Petr Vorel <[email protected]>

I wanted to apply your patch, and did a couple of updates to it (see below). However, there's a more fundamental problem to this package: it expects the linux package to be extracted/configured *before* the configuration of linux-backports. Unfortunately, this is not the case:
'linux' is only in LINUX_BACKPORTS_DEPENDENCIES, so it's only guaranteed to be here when linux-backports gets configured, not before.

I'm not sure yet of the possible solutions to this: add 'linux' to LINUX_BACKPORT_PATCH_DEPENDENCIES ? Use the linux extension mechanism as suggested by Arnout ?

Dear Petr Vorel,

Quoted 2 lines · Petr Vorel

https://backports.wiki.kernel.org

Quoted 1 line

Signed-off-by Petr Vorel <[email protected]>

I wanted to apply your patch, and did a couple of updates to it (see below). However, there's a more fundamental problem to this package: it expects the linux package to be extracted/configured *before* the configuration of linux-backports. Unfortunately, this is not the case:
'linux' is only in LINUX_BACKPORTS_DEPENDENCIES, so it's only guaranteed to be here when linux-backports gets configured, not before.

So, when you run 'make linux-backports-menuconfig' from a clean Buildroot tree (i.e without doing a full 'make'), you get:

thomas at skate:~/projets/buildroot (master)$ make linux-backports-menuconfig
yes "" | /usr/bin/make -j5 -C /home/thomas/projets/buildroot/output/build/linux-backports-3.18.1-1 HOSTCC="/usr/bin/gcc" HOSTCFLAGS="" ARCH=arm INSTALL_MOD_PATH=/home/thomas/projets/buildroot/output/target CROSS_COMPILE=" /home/thomas/projets/buildroot/output/host/usr/bin/arm-linux-" DEPMOD=/home/thomas/projets/buildroot/output/host/sbin/depmod KLIB_BUILD=/home/thomas/projets/buildroot/output/build/linux-4.0 KLIB=/home/thomas/projets/buildroot/output/target oldconfig make[1]: Entering directory '/home/thomas/projets/buildroot/output/build/linux-backports-3.18.1-1'
/--------------

| Your kernel headers are incomplete/not installed.
| Please install kernel headers, including a .config
| file or use the KLIB/KLIB_BUILD make variables to
| set the kernel to build against, e.g.
|   make KLIB=/lib/modules/3.1.7/
| to compile/install for the installed kernel 3.1.7
| (that isn't currently running.)

\--
Makefile:40: recipe for target 'oldconfig' failed
make[1]: *** [oldconfig] Error 1
make[1]: Leaving directory '/home/thomas/projets/buildroot/output/build/linux-backports-3.18.1-1' package/linux-backports/linux-backports.mk:38: recipe for target '/home/thomas/projets/buildroot/output/build/linux-backports-3.18.1-1/.stamp_kconfig_fixup_done' failed
make: *** [/home/thomas/projets/buildroot/output/build/linux-backports-3.18.1-1/.stamp_kconfig_fixup_done] Error 2

This is because output/build/linux-4.0 is currently empty, since the linux package has not been extracted yet.

Quoted 5 lines

Dear Petr Vorel,

Quoted 2 lines · Petr Vorel

https://backports.wiki.kernel.org

Quoted 8 lines

Quoted 1 line

Signed-off-by Petr Vorel <[email protected]>

I wanted to apply your patch, and did a couple of updates to it (see below). However, there's a more fundamental problem to this package: it expects the linux package to be extracted/configured *before* the configuration of linux-backports. Unfortunately, this is not the case:
'linux' is only in LINUX_BACKPORTS_DEPENDENCIES, so it's only guaranteed to be here when linux-backports gets configured, not before.

Perhaps that's a problem in the kconfig infrastructure. The configure step
depends on the DEPENDENCIES, and I'd consider the *config targets conceptually part of the configure step. Currently, *config only depends on the patch step (through $(2)_KCONFIG_FILE), perhaps we should add the depends step to that.

Well, I would not be very happy with that, since that would make the following use-case a real pain:

    $ make foo_defconfig
    $ make linux-menuconfig

Currently, all it needs is the linux kernel to be extracted and patched, and none of its depedencies to be built. Otherwise, it would require the toolchain to be built, plus a sh.tload of other stuff (lzo, for one, and all its own dependencies).

Dear Yann E. MORIN,

Quoted 10 lines · Yann E. MORIN

Well, I would not be very happy with that, since that would make the following use-case a real pain:

    $ make foo_defconfig
    $ make linux-menuconfig

Currently, all it needs is the linux kernel to be extracted and patched, and none of its depedencies to be built. Otherwise, it would require the toolchain to be built, plus a sh.tload of other stuff (lzo, for one, and all its own dependencies).

We could remove the mandatory host-lzo dependency from the linux package, by adding an option for that. Remember the recent patches also adding host-xz to the dependencies of linux, which I rejected?

This would leave host-kmod as the only dependency of the linux package I believe. But well host-kmod as AUTORECONF = YES, so it pulls a whole bunch of crap.

I agree that being able to do "make <foo>-menuconfig" without waiting too long is really a great feature.

Thomas

Thank you Thomas for testing, thanks a lot to all of you for the comments. Sorry that I didn't test it well, I didn't expect to be able to use 'make menuconfig' without calling make or 'make linux-backports' before.

I send v5 where I integrated Thomass' changes. So is it blind alley (if you don't want to tweak custom requirements), and I should try to add it as linux extension using integration strategy?

Dear Yann E. MORIN,

Quoted 10 lines · Yann E. MORIN

Well, I would not be very happy with that, since that would make the following use-case a real pain:

    $ make foo_defconfig
    $ make linux-menuconfig

Currently, all it needs is the linux kernel to be extracted and patched, and none of its depedencies to be built. Otherwise, it would require the toolchain to be built, plus a sh.tload of other stuff (lzo, for one, and all its own dependencies).

We could remove the mandatory host-lzo dependency from the linux package, by adding an option for that. Remember the recent patches also adding host-xz to the dependencies of linux, which I rejected?

This would leave host-kmod as the only dependency of the linux package I believe. But well host-kmod as AUTORECONF = YES, so it pulls a whole bunch of crap.

However, we can add the dependency specifically for linux-backports. There is
something to be said for the reasoning that usually/sometimes you don't need the dependencies to be present, so doing it per package sounds OK.

So in this case, adding

$(LINUX_BACKPORTS_KCONFIG_FILE): linux

to linux-backports.mk should be sufficient.

Dear Arnout Vandecappelle,

Quoted 6 lines · Arnout Vandecappelle

However, we can add the dependency specifically for linux-backports. There is
something to be said for the reasoning that usually/sometimes you don't need the dependencies to be present, so doing it per package sounds OK.

So in this case, adding

Quoted 3 lines

$(LINUX_BACKPORTS_KCONFIG_FILE): linux

to linux-backports.mk should be sufficient.

If we do this, we must also keep the 'linux' dependency in LINUX_BACKPORTS_DEPENDENCIES as well, so that the package infra remains aware of this dependency.

Quoted 15 lines

Dear Yann E. MORIN,

Quoted 10 lines · Yann E. MORIN

Well, I would not be very happy with that, since that would make the following use-case a real pain:

    $ make foo_defconfig
    $ make linux-menuconfig

Currently, all it needs is the linux kernel to be extracted and patched, and none of its depedencies to be built. Otherwise, it would require the toolchain to be built, plus a sh.tload of other stuff (lzo, for one, and all its own dependencies).

Quoted 7 lines

We could remove the mandatory host-lzo dependency from the linux package, by adding an option for that. Remember the recent patches also adding host-xz to the dependencies of linux, which I rejected?

This would leave host-kmod as the only dependency of the linux package I believe. But well host-kmod as AUTORECONF = YES, so it pulls a whole bunch of crap.

As mentioned before, it pulls in the toolchain as well. That's a lot worse than
host-lzo and host-xz - even extracting an external toolchain takes longer than host-xz (at least for me).

However, we can add the dependency specifically for linux-backports. There is
something to be said for the reasoning that usually/sometimes you don't need the dependencies to be present, so doing it per package sounds OK.

So in this case, adding

$(LINUX_BACKPORTS_KCONFIG_FILE): linux

to linux-backports.mk should be sufficient.