[Solved] Recompile a kernel module with one custom modification?

[temach]

I have a non compliant usb device that I want to work with my Orange Pi Lite board.

I know how to make it work under Arch linux. For that I need to edit source for the usb generic hid driver (kernel/drivers/hid/hid-core.c), recompile the usb kernel module and reinstall it to intramfs (mkinitcpio -p linux). To recompile kernel module I followed this guide: https://wiki.archlinux.org/index.php/Compile_kernel_module

 

What procedure do I need to follow under Armbian?

 

One way is to set up a development environment on a PC, with Virtual Box running Ubuntu Xenial, etc. Recompile the whole armbian and copy the compiled kernel module over to Orange Pi Lite.

 

But it takes a long time. Is there any way to recompile a kernel modue directly on the board?

 

Thanks for your time.

[Igor]

https://docs.armbian.com/User-Guide_Advanced-Features/#how-to-build-a-wireless-driver

[zador.blood.stained]

I know how to make it work under Arch linux. For that I need to edit source for the usb generic hid driver (kernel/drivers/hid/hid-core.c), recompile the usb kernel module and reinstall it to intramfs (mkinitcpio -p linux).

hid-core.c is a built-in object, so full kernel recompilation is required. Compiling the kernel on the board itself is possible, but there is no automation for this process yet, so you have to do everything manually - clone the sources, grab and apply the patches, grab the kernel config, compile and install resulting packages.

[temach]

After more looking around I found this thread: https://forum.armbian.com/index.php/topic/574-minimum-steps-to-build-a-kernel-module-for-latest-armbian-release/

 

Can I just use Igor's lib tool on the Orange Pi Lite?

 

That should automate everything.

[Igor]

Can I just use Igor's lib tool on the Orange Pi Lite?

Nope. It's a tool to run on a x86 desktop PC (cross compile).

[temach]

In the end I decided to go with creating a x-compile environment to get a patched hid.ko.gz

However I just noticed that my current armbian does not have a hid.ko.gz module. It has only g_hid.ko.gz

 

So would I go about installing a hid.ko.gz module?

 

my current setup: (uname -r)

Linux orangepilite 3.4.112-sun8i #10 SMP PREEMPT Sun Oct 23 16:06:55 CEST 2016 armv7l GNU/Linux

Legacy Debian Jessie

[zador.blood.stained]

Please read my message again. In current Armbian config

CONFIG_HID=y

so it's a built-in, not a module, and hid-core.c ends up in the main kernel binary (zImage), so, as I said before, full kernel recompilation is required to patch this file.

[temach]

Alright, I will just leave the instructions here for the record:

 

So I went with x-compiling.

 

(looks like now there is a vargrand config to set up the x-compile environment, so you can use that)

 

Installed VitrualBox & put Ubuntu Xenial on it.

sudo apt-get install linux-headers-$(uname -r) build-essentials

Then according to https://github.com/igorpecovnik/lib

I git cloned the lib

Then edited the compile.sh with the following options:

 

 

 

KERNEL_ONLY="yes" # leave empty to select each time, set to "yes" or "no" to skip dialog prompt
KERNEL_CONFIGURE="no" # change provided kernel configuration
CLEAN_LEVEL="make,debs" # comma-separated list of clean targets: "make" = make clean for selected kernel and u-boot,
# "debs" = delete packages in "./output/debs" for current branch and family,
# "alldebs" - delete all packages in "./output/debs", "images" = delete "./output/images",
# "cache" = delete "./output/cache", "sources" = delete "./sources"

DEST_LANG="en_US.UTF-8" # sl_SI.UTF-8, en_US.UTF-8

# advanced
KERNEL_KEEP_CONFIG="no" # do not overwrite kernel config before compilation
EXTERNAL="no" # build and install extra applications and drivers
EXTERNAL_NEW="no" # compile and install or install prebuilt additional packages
CREATE_PATCHES="yes" # wait that you make changes to uboot and kernel source and creates patches
FORCE_CHECKOUT="yes" # ignore manual changes to source
BUILD_ALL="no" # cycle through available boards and make images or kernel/u-boot packages.
# set KERNEL_ONLY to "yes" or "no" to build all packages/all images
BUILD_DESKTOP="no"
BOARD="orangepilite"
BRANCH="default"
RELEASE="jessie"

 

 

 

Then I run ./compile.sh with sudo.

 

Then when the script got to kernel compilation, I was prompted to edit the code and continue.

So I went ahead and modified the sources/linux-sun8i/sun8i/drivers/hid-core.c

Then I hit enter to let compilation continue and it told me that a patch was generated.

 

However that patch did not seem to get applied. So I moved the patch into userpatches/kernel/sun8i-default/my-kernel-patch.patch

and restarted the whole compile process (this time I compiled with CREATE_PATCHES="no")

 

In the end I got the deb files in the output

 

 

.
├── extra
├── jessie
│   └── linux-jessie-root-orangepilite_5.24_armhf.deb
├── linux-firmware-image-sun8i_5.24_armhf.deb
├── linux-headers-sun8i_5.24_armhf.deb
├── linux-image-sun8i_5.24_armhf.deb
└── linux-u-boot-orangepilite_5.24_armhf.deb

 

 

 

I used scp to copy them over to the orange pi lite.

After reading this thread: https://forum.armbian.com/index.php/topic/1315-custom-kernel-and-apt-get-update/

I realised that I only needed the headers, image and firmware debs. So I went ahead and installed them

with "sudo dpkg -i *.deb" (after removing u-boot deb package).

 

Then I pinned them, so they dont get changed on the next "apt-get upgrade".

And it works!

Thanks everyone!

 

Overall the toolchain is a bit difficult to grasp (argh, and the constant recompiles are off putting!), but serious kudos to you for creating and maintaning it! Because it actually works!