Missing file in JetPack 7.2 kernel sources

Robotics & Edge Computing Jetson Systems Jetson Thor
1

Hi NV,

While building JetPack 7.2 and working on the Kernel Customization step, I failed to copy the compiled DTB files to <install-path>/Linux_for_Tegra/kernel/dtb/. The system throws this error: cp: cannot stat 'kernel-devicetree/generic-dts/dtbs/*': No such file or directory

It looks like some source files are missing. I compared the packages and noticed that in JetPack 7.1, the kernel-devicetree folder exists inside public_sources.tbz2\public_sources.tar\Linux_for_Tegra\source\kernel_oot_modules_src.tbz2\kernel_oot_modules_src.tar\. However, this folder is nowhere to be found in the JetPack 7.2 equivalent tarballs.

Is it acceptable to copy the kernel-devicetree folder from JetPack 7.1 over to JetPack 7.2 to complete the build, or has the device tree structure changed in 7.2?

Or did I miss any specific step during the setup process?

Thanks!!

2

It might be

wget https://developer.nvidia.com/downloads/embedded/L4T/r39_Release_v2.0/sources/public_sources.tbz2

tar xf public_sources.tbz2

cd Linux_for_Tegra/source
tar xf kernel_src.tbz2
tar xf kernel_oot_modules_src.tbz2
tar xf nvidia_kernel_display_driver_source.tbz2
tar xf nvidia_unified_gpu_display_driver_source.tbz2

./source_sync.sh
5

Hi @whitesscott ,

Thanks for your reply.

I tested the steps you provided, but the kernel-devicetree folder is still missing.

However, I managed to find a workaround. I copied all files from source/build/nvidia-public/devicetree/generic-dtbs directly into Linux_for_Tegra/kernel/dtb/, and everything is working fine now.

Thanks!!

6

Hi @SamM11,

I’m faced with the kernel customization task, i.e. adding uinput module. I’ve never compiled the kernel before. Were you following instructions available somewhere? I’m looking for a lowest learning curve to complete my task.

7

Hi @pauljurczak ,

I follow this Developer Guide step Kernel Customization — NVIDIA Jetson Linux Developer Guide
to custom my kernel.

Thanks!!

8

Thank you for the link. Do you know if kernel modules like uinput or usbtouchscreen are available there?

9

CONFIG_INPUT_TOUCHSCREEN=y # is builtin

I have two automated scripts I can provide. I just modified them to use Jetpack 7.2. I’m doing a test: full kernel, modules, dtbs build. I’ll email you the uinput.ko in about 10 minutes. It is my build test to confirm automated method works.

10

Attached are two scripts and uinput.ko. I test built uinput.ko on my Thor. The scripts also should work on x86_64/amd64 but I’ve not tested them on x86_64 since updating them to download source / compile Jetpack 7.2; that worked with Jetpack 7.1.

jetpack-download-extract.sh should be run first.
nvbuild-kernel-dtb-and-Modules.sh should be run second.

cp uinput.ko.txt /lib/modules/6.8.12-1021-tegra/kernel/drivers/input/misc/uinput.ko
sudo depmod -a

modinfo uinput

filename:       /lib/modules/6.8.12-1021-tegra/kernel/drivers/input/misc/uinput.ko
license:        GPL
description:    User level driver support for input subsystem
author:         Aristeu Sergio Rozanski Filho
alias:          devname:uinput
alias:          char-major-10-223
depends:
intree:         Y
name:           uinput
vermagic:       6.8.12-1021-tegra SMP preempt mod_unload modversions aarch64
scott@chithor:~$ sudo modprobe uinput
scott@chithor:~$ lsmod |grep uinput
uinput                 20480  0

ls -l /dev/uinput
crw------- 1 root root 10, 223 Jun  4 22:35 /dev/uinput

menuconfig:  Device Drivers                                                                            │
  │       -> Input device support                                                                    │
  │         -> Generic input layer (needed for keyboard, mouse, ...) (INPUT [=y])                    │
  │           -> Miscellaneous devices (INPUT_MISC [=y])                                             │
  │ (1)         -> User level driver support (INPUT_UINPUT [=n])

nvbuild-kernel-dtb-and-Modules.sh.txt (3.5 KB)
jetpack-download-extract.sh.txt (4.4 KB)
uinput.ko.txt (144.1 KB)

11

Thank you. I will read the guide and try to build in the next day or two.