Linux Kernel ds2490 driver

[Brian C. Lane]

A digitemp user recently reported having problems using the ds2490
adapter on Fedora 33 (I approved the post to the list, but don't see it
here yet). This has been a problem for years, and I used to suggest
using modprobe -r ds2490 to remove it.

But that no longer works and it actually locks up the driver! You
have to reboot to kill the modprobe process :/

I've updated the README with this new section explaining how to fix it:

Problems with Linux Kernel ds2490 driver
----------------------------------------

The Linux kernel has included a ds2490 driver module for quite some time now.
This module will conflict with `digitemp_DS2490` use unless you unload it or
block it from being loaded. In the past I've recommended using `modprobe -r
ds2490` to remove the module, but this no longer works correctly on some
systems (I've tested it on Fedora 32 with kernel 5.10.22). It locks up the
`modprobe -r ds2490` process and you need to reboot to clear it.

The preferred way is to create a module blacklist file in
`/etc/modprobe.d/ds2490-blacklist.conf` with the contents being:

```
# ds2490 driver interferes with digitemp_DS2490 operation
blacklist ds2490
```

and then reboot. You can also test this by adding `modprobe.blacklist=ds2490` to
the kernel cmdline at boot time.

--
https://www.brianlane.com