The 2020 VISA driver from National Instruments (NI-VISA) for linux systems does not support linux kernels versioned as 5.10.x. The problem comes from the kernel module 'nikal'. This repo contains patches required to make it work for for a Fedora 33 system running linux kernel 5.10.15.
The author of this patch has no deep knowledge of the linux kernel. The only thing he did was to navigate the 4.x and 5.x linux source trees for the related errors when trying to build nikal module from ni source files. He then applied changes according to the changes in the linux kernel for the relevant functions. Since the changes appeared to be superficial like renaming of entities, or using slightly different structures for data, the task was not very difficult. Having said that, these patches come with NO warranty whatsoever. The website [1][https://elixir.bootlin.com] was used to browse linux kernel sources.
To apply the changes, download this repo in some folder named tmp and copy
the nikal.c to destination. I.e.:
NIVERSION="20.0.0f0"
git clone https://github.com/ckutlu/nikal.git
rm -r /usr/src/nikal-$NIVERSION
cp -r tmp/kernel-5.10.15/nikal-$NIVERSION /usr/src/You can now reinstall the kernel modules necessary for the lib operation.
dkms autoinstallCheck out old branches for different ni & kernel combinations.