When using multiple softdep for a module, only one of them have effects about kmod HOT 2 OPEN

When using multiple softdep for a module, only one of them have effects

that's correct. The config parsing in kmod is designed so one config overrides a previously set one.

user configured softdeps in /etc/modprobe.d will just be ignored, making it effectively non-user configurable. I think this is undesirable.

that would be a bug... we should be respecting the precedence order as per MODPROBE.D(5) :
/lib/modprobe.d/.conf
/usr/local/lib/modprobe.d/.conf
/run/modprobe.d/.conf
/etc/modprobe.d/.conf

... with the latest files overriding what is set in the previous ones.

Improvements we could add to kmod:

1. Define a different syntax to extend a previous setting. so it does what you were expecting. systemd's units use a += for that. We could do something similar
2. Allow a setting to be removed (i.e. it should be possible to set a softdep to "empty" after it has been set by another file).

Thoughts?

from kmod.

that would be a bug...

ok then I suppose I am hitting this bug then. In lib/modules/<kernel ver>/modules.softdep I have:

softdep nvidia pre: ecdh_generic,ecdsa_generic

and in /etc/modprobe.d/abc.conf I have:

softdep nvidia post: nvidia-uvm

The latter has no effect.

I also found many modules are using softdep "wrong", for example in modules.softdep I saw:

softdep btrfs pre: blake2b-256
softdep btrfs pre: sha256
softdep btrfs pre: xxhash64
softdep btrfs pre: crc3

I found it hard to believe btrfs wrote all these just to load crc3.

from kmod.