I was messing with an untested device driver, and now I'm facing the consequences. I'll skip the details of what happened and get to the symptom. This box with Redhat Enterprise 4 used to boot with two HID device files in /dev: hiddev0 and hiddev1. Even when I would mess one of them up, a reboot would restore their original condition. Now I don't get hiddev1. I can create it anew with mknod, but it doesn't seem to work. It doesn't appear in /proc/bus/usb/devices.

There must be something in the boot procedure that cleans up /dev and
creates what needs to be created. So far I haven't been able to find it. Can someone set me straight?

I'll skip the details of what happened and get to the symptom.
Your choice. Remember that sharing more info is always better wrt clues.


Now I don't get hiddev1.
Anything interesting in syslog wrt USB?
If you post error messages please make sure you post *exact* ones.


There must be something in the boot procedure that cleans up /dev
Most likely culprits are Kudzu/devlabel (unlikely since it's HID) and devfs/udev.
Both devlabel and udev are tweakable.

Hardware detection on most systems I've seen lately is done by hotplug. There is a step while booting called "coldplug" which is really just running hotplug to do initial hardware detection (and rededication of previously detected devices)

Doesn't answer your question, but it might help.

Also, it is fun to play in the /sys pseudo file system. This might help prove that the system sees the device at all (even if the driver is wrong). Note that /sys is not always a friendly place, but it is useful. I suggest looking in /sys/bus.

Good luck.

There it is. I new there was a folder for this.
This can also be useful. Be prepared to rename this directory, as it can fill quickly. (note this is on SuSE 9.3, I assume this will be the same on your system)

Thanks for the advice. Unfortunately I can't make any progress for a while because of a hardware problem. The device is a Tripp-Lite UPS. It's gone into a funny mode in which it won't talk to the USB port and I can't turn it off or make it self-test. Unplugging it doesn't help because, of course, it has a whopping big battery that will keep it going for a very long time. While messing around with software, I discovered that I was able to shut it off inadvertently. Maybe I did something even worse. Stay tuned.