[systemd-devel] how to bind to other drivers using systemd

[Flavio Leitner]

Hello,

I am looking for guidance on how to properly resolve driver binding
with systemd (which seems to me the best place to do that).

Today we have 2 or more kernel drivers for the same device.  For
instance, we can use the standard NIC driver, or UIO driver or even
VFIO driver.

Since all three drivers work for the same device, the system admin
needs to tell which one is desired.

Ideally this shouldn't be limited to NIC drivers.

Also not limited to PCI devices.

It should be possible to start/stop which means go back and forth
with the drivers.

It should provide some level of dependency because other services
might need the device running with specific driver.

One possible option is to use something like to dev-vfio at .service
or dev-uio at .service, but then it would require a template for every
possible driver out there and track down the original driver info
somewhere.

Next option would be something generic like driver-bind at .service
plus a configuration file mapping devices to drivers.  This seems
rather confusing and not really how systemd seem to work.

Udev rules work for matching any kind of device and could bind to
a specific driver, but it seems to be one-shot only.  Also that a
udev rule doesn't look like a service managed by admins.

Thanks in advance.
fbl