PLDWWW: UdevFAQ

[prism]

Author: prism   Date: Sun Nov 13 12:16:44 2005 GMT
Module: PLDWWW   URL: http://www.pld-linux.org/UdevFAQ
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---- Page affected: UdevFAQ

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= PLD udev FAQ (udev-0.71-5) =

{{{
From: Fryderyk Dziarmagowski <freetz>
To: pld-users-pl at lists.pld-linux.org
Subject: [FAQ] PLD udev FAQ
Date: Sun, 6 Nov 2005 21:59:31 +0100
X-Translated-By: Michał Łukaszek <prism>
}}}

== Which kernel version is recommended for proper work of udev/udev-hotplug? ==

''Minimum recommended version is 2.6.12.x'' (udev hotplug won't work with the older)

== Udev doesn't load all modules for me! ==

...that's because it loads only modules for PCI devices that meet the requirements included in udev rules. That rules allow auto-loading feature only for internal USB devices (hubs), such as `uhci-hcd` or `ehci-hcd`.

If you want to get the modules of all devices loaded automatically, enable `udevsynthetize` in `/etc/udev/udev.conf`. This is experimental and not fully tested though.

== What about hotplug? Will my pendrive work? ==

Hotplug included in current udev replaces the old hotplug completely. Paralell work of both is rather not advisable, so after udev's installation the old hotplug is uninstalled.
USB pendrive will work like a charm if you read answer no. 1.

== I'd like to connect my digital camera/scanner/other USB device to my computer. Do I have to mount `/proc/bus/usb` with proper permissions? ==

Absolutely not. Install `udev-digicam` package, add yourself to the digicam group, and udev's agent will do the rest, no matter if that's a scanner or other USB input device you connected.

== Can udev automatically mount partitions or cd drives it finds? ==

No. There are specialized programs for this, like `gnome-volume-manager`.

== I'm using nvidia-legacy and the `/dev/nvidia*` is not created! ==

That's a problem of nvidia (legacy) drivers. udev has nothing to do with it. Unfortunately, you must manually create proper device files using `mknod`.

== I have to manually load modules such as psmouse or evdev! Why? ==

The kernel's input layer is broken. It's said to be fixed in 2.6.15...

== Do I have to add the usb-controller alias in `/etc/modprobe.conf`? ==

No. All `*-hcd` modules are loaded automatically.

== I get the error messages about failed agents in my system's logs! ==

They don't work because they are not there - unless you installed `udev-digicam`, which has the usb agent. That udev warnings in logs don't look nice, but they are absolutely harmless. This will be fixed if there will be a person willing to fix it ;)

== I've got a problem which is not covered here. How do I diagnose it? ==

Set `udev_log` to "info" in `/etc/udev/udev.conf` to improve verbosity of udev, use `udevmonitor` (`man udevmonitor`) to get even more infomation, check the linux-hotplug list's archive http://marc.theaimsgroup.com/?l=linux-hotplug-devel.
If still unsure, ask your question on PLD mailing lists.