[SOLVED] Custom kernel + Archlinux for unsupported board

[riltonf]

According to download page "The released downloads are designed for the specific systems above; however, our package repositories work with any ARM device compatible with ARMv5, ARMv6, ARMv7-a, or ARMv8-a AArch64 instructions. Simply download the tarball that best fits and supply your own kernel." I have to supply my own kernel since my board is not supported.

I've never done this and it's my first time digging into embedded Linuxes. My board is an Ultra96v2 http://avnet.me/ultra96-v2, it's an MPSoC with an fpga and arm cores in one chip. The chip on it is from Xilinx.

Using Petalinux tool from xilinx I built a custom kernel for my board with all the peripherals working using a board support file. Then I just extracted the arch linux rootfs into my root partition and booted it up. Everything worked as normal, no real issues (after adding the peripheral kernel modules), I got networking online and updated my system. Pacman went on and updated the mainline kernel, at the time of writing this was 5.3.10-1-ARCH. The custom kernal I was using is 4.14.0-xilinx-v2018.3 (made using petalinux 2018.3). Because of the way my u-boot is set up, it always boots my custom kernel.

What do I lose out on if I'm not using the mainline kernel, aside from security updates and some features that I'm not using? Will my system eventually break? And is there any way to merge my custom kernel with the mainline one, if that makes any sense? I'd use the mainline kernel but I need specific tools on my board like FPGA Manager that is used to program the fpga which are under /sys/class/fpga_manager

Any ideas?

[moonman]

You are not losing much if you have everything you need in the kernel you have. Newer kernels will have the security patches, like you mentioned, and may introduce new features like exfat in-kernel module for example, or a driver for a WiFi dongle.

It is possible it will break eventually as systemd stops supporting the kernel version you have or if it starts requring a feature your kernel doesn't have, but looking at the version you have you should be fine for a while. The oldest kernel we have in our repository is 3.10 which is quite a bit older than yours, and it works.

[riltonf]

Thanks for the reassurance. Later on I'll try and see if I can make a PKGBUILD for this specific board.