diff options
Diffstat (limited to 'README')
| -rw-r--r-- | README | 20 |
1 files changed, 10 insertions, 10 deletions
@@ -13,7 +13,7 @@ Tools and rules shipped by udev are not public API and may change at any time. Never call any private tool in /lib/udev from any external application; it might just go away in the next release. Access to udev information is only offered by udevadm and libudev. Tools and rules in /lib/udev and the entire contents of -the /dev/.udev directory are private to udev and do change whenever needed. +the /run/udev directory are private to udev and do change whenever needed. Requirements: - Version 2.6.34 of the Linux kernel with sysfs, procfs, signalfd, inotify, @@ -59,21 +59,21 @@ Requirements: available. - Some udev extras have external dependencies like: - libacl, libglib2, libusb, usbutils, pciutils, and gperf. + libacl, libglib2, usbutils, pciutils, and gperf. All these extras can be disabled with configure options. Setup: - At bootup, the /dev directory should get the 'devtmpfs' filesystem mounted. Udev manages the permissions and ownership of the kernel-created device nodes, and udev possibly creates additional symlinks. If needed, udev also - works on an empty 'tmpfs' filesystem, but some static device nodes like - /dev/null, /dev/console, /dev/kmsg are needed to be able to start udev itself. + works on an empty 'tmpfs' filesystem, but some device nodes like + /dev/null, /dev/console, /dev/kmsg should be created before udevd is started. - The udev daemon should be started to handle device events sent by the kernel. - During bootup, the kernel can be asked to send events for all already existing - devices so that they too can be configured by udev. This is usually done by: - /sbin/udevadm trigger --type=subsystems - /sbin/udevadm trigger --type=devices + During bootup, the events for already existing devices can be replayed, so + that they are configured by udev. This is usually done by: + /sbin/udevadm trigger --action=add --type=subsystems + /sbin/udevadm trigger --action=add --type=devices - Restarting the daemon never applies any rules to existing devices. @@ -82,13 +82,13 @@ Setup: Operation: - Based on events the kernel sends out on device creation/removal, udev - creates/removes device nodes in the /dev directory. + creates/removes device nodes and symlinks in the /dev directory. - All kernel events are matched against a set of specified rules, which possibly hook into the event processing and load required kernel modules to set up devices. For all devices, the kernel exports a major/minor number; if needed, udev creates a device node with the default kernel - name. If specified, udev applies permissions/ownership to the device + device name. If specified, udev applies permissions/ownership to the device node, creates additional symlinks pointing to the node, and executes programs to handle the device. |