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| -rw-r--r-- | README | 44 |
1 files changed, 22 insertions, 22 deletions
@@ -3,17 +3,17 @@ udev - Linux userspace device management Integrating udev in the system has complex dependencies and may differ from distribution to distribution. A system may not be able to boot up or work reliably without a properly installed udev version. The upstream udev project -does not recommend to replace a distro's udev installation with the upstream +does not recommend replacing a distro's udev installation with the upstream version. The upstream udev project's set of default rules may require a most recent kernel release to work properly. This is currently version 2.6.31. 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 +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 content of -the /dev/.udev directory is private to udev and does change whenever needed. +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. Requirements: - Version 2.6.27 of the Linux kernel with sysfs, procfs, signalfd, inotify, @@ -31,7 +31,7 @@ Requirements: CONFIG_TMPFS_POSIX_ACL=y (user ACLs for device nodes) CONFIG_BLK_DEV_BSG=y (SCSI devices) - - Udev will not work with the CONFIG_SYSFS_DEPRECATED* option. + - Udev does not work with the CONFIG_SYSFS_DEPRECATED* option. - Unix domain sockets (CONFIG_UNIX) as a loadable kernel module may work, but it is not supported. @@ -41,46 +41,46 @@ Requirements: unusable because the kernel may create too many processes in parallel so that the system runs out-of-memory. - - The proc filesystem must be mounted on /proc, the sysfs filesystem must + - The proc filesystem must be mounted on /proc, and the sysfs filesystem must be mounted at /sys. No other locations are supported by a standard udev installation. - The system must have the following group names resolvable at udev startup: - disk, cdrom, floppy, tape, audio, video, lp, tty, dialout, kmem. - Especially in LDAP setups, it is required, that getgrnam() is able to resolve - these group names with only the rootfs mounted, and while no network is + disk, cdrom, floppy, tape, audio, video, lp, tty, dialout, and kmem. + Especially in LDAP setups, it is required that getgrnam() be able to resolve + these group names with only the rootfs mounted and while no network is available. - - To build all 'udev extras', libacl, libglib2, libusb, usbutils, pciutils, - gperf are needed. These dependencies can be disabled with the - --disable-extras configure option. + - The 'udev extras' has the following dependencies: + libacl, libglib2, libusb, usbutils, pciutils, and gperf. + These dependencies can be disabled with the --disable-extras configure option. Setup: - At bootup, the /dev directory should get the 'devtmpfs' filesystem - mounted. Udev will manage permissions and ownership of the kernel-created - device nodes, and possibly create additional symlinks. If needed, udev also + 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. - 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, to apply the configuration to these devices. This is usually done by: + 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 - - Restarting the daemon does never apply any rules to existing devices. + - Restarting the daemon never applies any rules to existing devices. - - New/changed rule files are picked up automatically, there is no daemon + - New/changed rule files are picked up automatically; there is no daemon restart or signal needed. Operation: - - Udev creates/removes device nodes in /dev, based on events the kernel - sends out on device creation/removal. + - Based on events the kernel sends out on device creation/removal, udev + creates/removes device nodes 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 setup devices. For all devices the kernel exports a major/minor - number, if needed, udev will create a device node with the default 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 node, creates additional symlinks pointing to the node, and executes programs to handle the device. @@ -90,7 +90,7 @@ Operation: http://www.kernel.org/pub/linux/utils/kernel/hotplug/libudev/ http://www.kernel.org/pub/linux/utils/kernel/hotplug/gudev/ -For more details about udev and udev rules see the udev(7) man page. +For more details about udev and udev rules, see the udev(7) man page. Please direct any comment/question to the linux-hotplug mailing list at: linux-hotplug@vger.kernel.org |