RTL8192EU being broken after every kernel upgrade

Support AUR
1

Hi!

Using KDE with 5.15-LTS on stable branch

I’m using the rtl8192eu-git driver from the AUR as without it the adapter can’t connect to any network (but sees them)

The problem is that the system update brings with it a kernel update, which is why I have to rebuild the driver, as it “falls off”. But building the driver requires running headers, and for this I need to restart the system after the update, and after restarting I have no internet to rebuild the driver

Please help, maybe I’m doing something wrong? Here is my usual full system update script (this is the only script I use since I rarely update the system)

# update mirrors
sudo pacman-mirrors --fasttrack --timeout 2

# upgrade all packages (normal + aur)
pamac upgrade --no-confirm --force-refresh --enable-downgrade --aur --devel

# install headers (required by the driver)
sudo pacman -S $(pacman -Qsq "^linux" | grep "^linux[0-9]*[-rt]*$" | awk '{print $1"-headers"}' ORS=' ') --noconfirm

# reinstall wifi driver (required if kernel was upgraded)
pamac build rtl8192eu-git --no-confirm
echo "blacklist rtl8xxxu" | sudo tee /etc/modprobe.d/rtl8xxxu.conf

# remove all junk packages
pamac remove --no-confirm --orphans

# clean installation caches
pamac clean --no-confirm --verbose --build-files --keep 0

# clean system as root
sudo bleachbit --clean firefox.cache firefox.crash_reports firefox.vacuum firefox.backup discord.vacuum discord.cache system.cache system.clipboard system.desktop_entry system.recent_documents system.rotated_logs system.tmp system.trash thumbnails.cache journald.clean system.localizations

# clean system as normal user
bleachbit --clean firefox.cache firefox.crash_reports firefox.vacuum firefox.backup discord.vacuum discord.cache system.cache system.clipboard system.desktop_entry system.recent_documents system.rotated_logs system.tmp system.trash thumbnails.cache journald.clean system.localizations

# send TRIM to SSD
sudo fstrim /

echo " "
echo " "
echo " "
echo " "
echo " "
echo " "
echo " "
echo "======= DONE ======="
2

This driver requires DKMS
If you set it (DKMS) up correctly - and have/install the appropriate kernel headers
the driver will be rebuilt and installed before you shut down and reboot.
So it will be available and work once you reboot.

3

I installing them during update every time

How can I do it?

4

look in Arch wiki for it?
or maybe here on the forum?

5

https://wiki.archlinux.org/title/Dynamic_Kernel_Module_Support

I dont see anything about “dkms setup”

If I understand the

User does not have to wait for a company, project, or package maintainer to release a new version of the module. Since the introduction of pacman hooks, the rebuild of the modules is handled automatically when a kernel is upgraded

correctly, pacman must rebuild modules on its own when updating the kernel. But the problem is that I install via AUR. Also, the Arch Wiki clearly states the concept

DKMS modules automatically rebuilt when a new kernel is installed

and does not include any configuration. This should work out of the box

6

It should indeed - and it does for me.

But I’m not on Manjaro.
and thus can’t really gauge your problem - slightly different system …
… but it should work just the same, provided the correct headers for the used kernel are installed

Installing a new kernel version for me triggers the rebuilding of any DKMS modules/drivers

before a reboot

they are thus present and working
once rebooted

Perhaps - just perhaps
you could use some other tool than pamac
(like yay, for example)
to update your system (your systems AUR packages)?

7

For me, installing new kernels not triggers rebuilding and I can`t rebuild driver by my own without reboot. I neved changed system configs so it’s default Manjaro behavior

I used yay before and there are the same problem

8

Then I can’t be really of help
but just refer you to the documentation for Manjaro on how to use it (DKMS) properly.

The whole purpose of it is to compile/provide working software/drivers
to make a flawless reboot possible
… instead of dealing with the problem on a case by case basis
after/when you already have a disfunctional driver after boot, because it is not matching the kernel you are using

9

Try 8192eu-dkms package from AUR.

10

… that’s probably it :wink:
although in the dependencies of the other one was: DKMS …

11

The package you are using is not based on dkms - which is why have to rebuild after each kernel sync.

In such case you need to maintain the driver manually.

A search in the AUR database AUR (en) - Packages shows a dkms based package for your devices

https://aur.archlinux.org/packages/8192eu-dkms-git

Clone the package

git clone https://aur.archlinux.org/8192eu-dkms-git
cd 8192-dkms-git
makepkg

Once you have the kernel headers in place for your kernel - I noted 5.15 LTS - the headers will be synced when you sync your system and with the package installed - dkms will rebuild the modules when new kernel (same release e.g. 5.15) is synced.

That is because dkms setup is not needed on an Arch based system - the command is used on Debian based systems.

When you install dkms and kernel headers for your actual kernel(s) and any package labelled -dkms you will get the necessary files for building the module in question.

That is one of the reasons you - unless experienced in building from source - should avoid manually building kernel modules or other binaries - using make && sudo make install. Another reason is the likelihood of getting file conflicts when syncing repo packages onto the system.

An example on how it works is the repo package virtualbox-host-dkms. To get the full picture of what happens I invite you to download the packages - unpack then into a temporary folder and examine exactly what they do. It is very educating and what I do when I don’t quite understand what is going on.

Example to fetch the files into a temporary folder in your home

mkdir ~/temp
sudo pacman -S --downloadonly dkms virtualbox-host-dkms --cachedir ~/temp

The package contains the c source and headers for the virtualbox host modules and installs those to /usr/src along with the necessary make files and dkms configuration.

The package also installs a configuration in the distribution wide location /usr/lib/modules-load.d

The package pulls the package dkms as an obvious dependency - which in turn contains pacman hooks which are executed when a kernel sync condition exist.

The logic behind hooks is quite simple and if the pkgbuild for RTL8192EU is based on dkms the modules are rebuild when syncing a new kernel.

12

Thanks a lot for such a detailed answer! Do I need to manually check for up-to-date headers each time?

13

Each time? linuxXXX-headers package is just like any other package - it gets updated with the rest of packages. You only install new headers with new kernel.

2 Likes
14

No you don’t.

When a package - in this case linux515-headers has been installed onto the system - all subsequent sync will include it if the package has changed.

Only in the event you are moving to a new kernel release e.g. 5.18 or the next LTS you will have to explicitly install kernel headers for that kernel.

Unlike pacman - which must be specifically instructed - if you use mhwd-kernel to move to a new kernel and you have the headers for the current kernel installed mhwd-kernel will install the headers without being specifically instructed to - thus helping you by applying your current kernel related packages.

1 Like