Consistent Device Initialization

[g2admdb]

The lengthy discussion about the hotplug-20040923 changes has some good points that are easily lost in the volume.

The significant issue raised is that from a user/admin perspective, device initialization needs to be consistent independent of whether the device was present at boot or is plugged in later. Settings for the configuration of a device for coldplugging, hotplugging or both must be in only one place. More than that invites errors due to the duplication of information.

The particular mechanism used to handle the various cases isn't important. What matters is that all cases are handled in a consistent way for users/admins.

Hotplug with udev does nice things, but If loading modules during boot isn't supposed to be its job that's fine. Modules.autoload works and a tool could be developed to initialize the list for people. But, one thing to remember is that the hotplug scripts do more than just load kernel modules.

In my particular case, a usb scanner needs to have the permissions and ownership set on /dev/bus/usb/xxx/yyyy so that sane will work as a non-root user. The hotplug handler does this when the device is unplugged/replugged. This also needs to be done at boot. No kernel module is involved so modules.autoload does not apply.

It appears that using the hotplug mechanism (via coldboot) for setting up boot devices has issues and sometimes causes system problems. If hotplug isn't the way to handle boot devices, then what needs to be created to do all the other things hotplug handlers do for devices? Whatever is proposed should somehow reuse the hotplug handlers/agents to prevent duplication of code.