After upgrade to 15.4 the key combinations for keyboard backlight, doesn't works anymore

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#1

on my son’s laptop CLEVO NS50MU linux ultrabook after upgrade from 15.3 to LEAP 15.4 with KDE the key combinations Fn+keys on the numeric keypad, doesn’t works anymore, the combinations Fn+F1 or F2 and other works, with 15.3 they worked.
what I can do to have the keys for keyboard backlight working?

#2

I met with something similar in the past, possibly due to bad compatibility of the firmware (aka BIOS) code in some laptops and the kernel.
You may try to add 'acpi_osi= ’ to the kernel boot command line so that it looks like, for instance:

linux /boot/vmlinuz-5.14.21-xxx-default root=yyy splash=silent quiet acpi_osi=

To try that hit “E” at the GRUB screen, search and edit the relevant line and then hit F10 to boot.
If it works, a permanent fix is editing the “GRUB_CMDLINE_LINUX_DEFAULT=” line of file /etc/default/grub and then run ‘grub2-mkconfig -o /boot/grub2/grub.cfg’ to update grub.cfg
If interested you may find further details in the kernel documentation, for instance here

#3

I own a TUXEDO notebook (which is a CLEVO P65x sold by TUXEDO) and I need a special kernel module called tuxedo_keyboard to get the keyboard backlight switches working.

Check with CLEVO (or your notebook dealer) if you can get the sources for such a module.

I got mine from here (if you are lucky they will work for your son’s notebook as well).

#4

manythanks, it was tuxedo_keyboard that was installed but it seems to need also this
tuxedo-keyboard-kmp-default - TUXEDO Computers Kernel Module
taken from here obs://build.opensuse.org/home:sleepingtux