Masahiro Yamada wrote:

On Thu, Dec 7, 2023 at 4:48 AM Michal Suchanek [off-list ref] wrote:

quoted

Some distributions aim at shipping all files in /usr.

The path under which kernel modules are installed is hardcoded to /lib
which conflicts with this goal.

When kmod provides kmod.pc, use it to determine the correct module
installation path.

With kmod that does not provide the config /lib/modules is used as
before.

While pkg-config does not return an error when a variable does not exist
the kmod configure script puts some effort into ensuring that
module_directory is non-empty. With that empty module_directory from
pkg-config can be used to detect absence of the variable.

Signed-off-by: Michal Suchanek <redacted>
---
v6:
  - use ?= instead of := to make it easier to override the value

"KERNEL_MODULE_DIRECTORY=/local/usr/lib/modules make modules_install"
will override the install destination, but
depmod will not be not aware of it.

How to avoid the depmod error?

I think the depmod -b option can be used to ran depmod in an arbitrary 
location:

The following options are useful for people managing distributions:
     -b, --basedir=DIR    Use an image of a module tree.

Woody

quoted

  - use shorter expression for determining the module directory assuming
    it's non-empty
---
  Makefile | 4 +++-
  1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/Makefile b/Makefile
index 511b5616aa41..84f32bd563d4 100644
--- a/Makefile
+++ b/Makefile

@@ -1081,7 +1081,9 @@ export INSTALL_DTBS_PATH ?= $(INSTALL_PATH)/dtbs/$(KERNELRELEASE)
  # makefile but the argument can be passed to make if needed.
  #

-MODLIB = $(INSTALL_MOD_PATH)/lib/modules/$(KERNELRELEASE)
+export KERNEL_MODULE_DIRECTORY ?= $(or $(shell pkg-config --variable=module_directory kmod 2>/dev/null),/lib/modules)
+
+MODLIB = $(INSTALL_MOD_PATH)$(KERNEL_MODULE_DIRECTORY)/$(KERNELRELEASE)
  export MODLIB

  PHONY += prepare0
--

2.42.0

--
Best Regards
Masahiro Yamada