Re: [PATCH] linux-module: make sure out-of-tree modules win over built-in

["Bezdeka, Florian" <florian.bezdeka@siemens.com>]

On Thu, 2022-08-25 at 22:40 +0200, Henning Schild wrote:
> If we built an out of tree module that happens to be already part of the
> kernel, 
> 

This hopefully does not happen in the wild and is likely a very special
situation we're facing internally while working on upstreaming some
driver stuff.

I'm not sure if this is really relevant for Isar itself. If the
decision is "let's take it", I would vote for "disabled per default".

> we want to make sure depmod prefers the external one. In order
> to do so simply include a config file into every module package, by
> default using the kernels default INSTALL_MOD_DIR which is "extra".
> 
> Should there be multiple modules using different such directories, all
> recipes should set INSTALL_MOD_DIR listing them all in the desired
> order. That interface for multiple such very special modules is not nice
> but since they are pretty special it might be just good enough.
> 
> Reported-by: Pingfang Liao <Pingfang.Liao@siemens.com>
> Signed-off-by: Henning Schild <henning.schild@siemens.com>
> ---
>  meta/recipes-kernel/linux-module/files/debian/rules.tmpl | 1 +
>  meta/recipes-kernel/linux-module/module.inc              | 3 +++
>  2 files changed, 4 insertions(+)
> 
> diff --git a/meta/recipes-kernel/linux-module/files/debian/rules.tmpl b/meta/recipes-kernel/linux-module/files/debian/rules.tmpl
> index d3bd7dc30f21..abd3c88fac7e 100755
> --- a/meta/recipes-kernel/linux-module/files/debian/rules.tmpl
> +++ b/meta/recipes-kernel/linux-module/files/debian/rules.tmpl
> @@ -55,6 +55,7 @@ override_dh_auto_build:
>  
>  override_dh_auto_install:
>  	$(MAKE) -C $(KDIR) M=$(PWD) INSTALL_MOD_PATH=$(PWD)/debian/${PN} modules_install
> +	install -D -m 0644 $(PWD)/debian/${PN}.conf $(PWD)/debian/${PN}/usr/lib/depmod.d/${PN}.conf
>  
>  %:
>  	CFLAGS= LDFLAGS= dh $@ --parallel
> diff --git a/meta/recipes-kernel/linux-module/module.inc b/meta/recipes-kernel/linux-module/module.inc
> index b20ec32ae20a..475e7aef05ea 100644
> --- a/meta/recipes-kernel/linux-module/module.inc
> +++ b/meta/recipes-kernel/linux-module/module.inc
> @@ -29,9 +29,12 @@ TEMPLATE_FILES = "debian/control.tmpl \
>                    debian/rules.tmpl"
>  TEMPLATE_VARS += "KERNEL_NAME KERNEL_TYPE KERNEL_IMAGE_PKG KERNEL_HEADERS_PKG DEBIAN_BUILD_DEPENDS PN"
>  
> +INSTALL_MOD_DIR ?= "extra"
> +
>  do_prepare_build() {
>      cp -r ${WORKDIR}/debian ${S}/
>  
> +    echo "search ${INSTALL_MOD_DIR} built-in" > ${S}/debian/${PN}.conf
>      for module in ${AUTOLOAD}; do
>          echo "echo $module >> /etc/modules" >> ${S}/debian/postinst
>      done
> -- 
> 2.35.1
>