[OE-core] [PATCH] busybox: mdev: make mdev auto load modules at boot

[Khem Raj]

On Mon, Mar 5, 2018 at 12:22 AM, Quentin Schulz
<quentin.schulz at bootlin.com> wrote:
> Thanks to the MODALIAS line at the beginning of mdev.conf, mdev supports
> module auto probing on hotplug.
>
> However, this does not work for cold plugged modules (i.e. modules for
> devices that were probed before mdev is added as hotplug handler).
> Running mdev -s to replay hotplug events does not work in that case.
>
> Let's manually modprobe all modules in the rootfs.
>
> Taken from:
>  - https://github.com/buildroot/buildroot/commit/07f46c2b6daec44a6176039c90be67e66c4c2e42
>  - https://github.com/buildroot/buildroot/commit/b4fc5a180c81689a982d5c595844331684c14f51
>
> We need xargs to support zero termination of args so let's enable this
> configuration in the fragment for mdev.
>
> Signed-off-by: Quentin Schulz <quentin.schulz at bootlin.com>
> ---
>  meta/recipes-core/busybox/busybox/mdev.cfg | 2 ++
>  meta/recipes-core/busybox/files/mdev       | 1 +
>  2 files changed, 3 insertions(+)
>
> diff --git a/meta/recipes-core/busybox/busybox/mdev.cfg b/meta/recipes-core/busybox/busybox/mdev.cfg
> index 6aefe90e43..0d60fc9560 100644
> --- a/meta/recipes-core/busybox/busybox/mdev.cfg
> +++ b/meta/recipes-core/busybox/busybox/mdev.cfg
> @@ -9,3 +9,5 @@ CONFIG_SETSID=y
>  CONFIG_CTTYHACK=y
>
>  CONFIG_FEATURE_SHADOWPASSWDS=y
> +
> +CONFIG_FEATURE_XARGS_SUPPORT_ZERO_TERM=y
> diff --git a/meta/recipes-core/busybox/files/mdev b/meta/recipes-core/busybox/files/mdev
> index 8c9c06e96c..165b275256 100755
> --- a/meta/recipes-core/busybox/files/mdev
> +++ b/meta/recipes-core/busybox/files/mdev
> @@ -9,6 +9,7 @@ touch /dev/mdev.seq
>  #sysctl -w kernel.hotplug=/sbin/mdev
>  echo "/sbin/mdev" > /proc/sys/kernel/hotplug
>  mdev -s
> +find /sys/ -name modalias -print0 | xargs -0 sort -u -z | xargs -0 modprobe -abq
>

will this execute on every boot ?