3 The 'devtmpfs' filesystem is required now, udev will not create or delete
4 device nodes anymore, it only adjusts permissions and ownership of device
5 nodes and maintains additional symlinks.
7 A writable /run directory (tmpfs) is required now for a fully functional
10 The default 'configure' install locations have changed. Packages for systems
11 with the historic / vs. /usr split need to be adapted, otherwise udev will
12 be installed in /usr and not work properly. Example configuration options are
15 The default install location of the 'udevadm' tool moved from 'sbin'
16 to /usr/bin. Some tools expect udevadm in 'sbin'. A symlink to udevadm
17 needs to be manually created if needed.
19 Kernel modules are now loaded directly by linking udev to 'libkmod'. The
20 'modprobe' tool is no longer executed by udev.
22 The 'blkid' tool is no longer executed from udev rules. Udev links
23 directly to libblkid now.
25 Firmware is loaded natively by udev now, the external 'firmware' binary
28 All built-in tools can be listed and tested with 'udevadm test-builtin'.
30 The 'udevadm control --reload-rules' option has been renamed to '--reload'.
31 It reloads the kernel module configuration.
33 The systemd socket files use PassCredentials=yes, which requires systemd
36 The udev build system only creates a .xz tarball now.
46 The udev daemon moved to /lib/udev/udevd. Non-systemd init systems
47 and non-dracut initramfs image generators need to change the init
48 scripts. Alternatively the udev build needs to move udevd back to
49 /sbin or create a symlink in /sbin, which is not done by default.
51 The path_id, usb_id, input_id tools are built-in commands now and
52 the stand-alone tools do not exist anymore. Static lists of file in
53 initramfs generators need to be updated. For testing, the commands
54 can still be executed standalone with 'udevadm test-builtin <cmd>'.
56 The fusectl filesystem is no longer mounted directly from udev.
57 Systemd systems will take care of mounting fusectl and configfs
58 now. Non-systemd systems need to ship their own rule if they
59 need these filesystems auto-mounted.
61 The long deprecated keys: SYSFS=, ID=, BUS= have been removed.
63 The support for 'udevadm trigger --type=failed, and the
64 RUN{fail_event_on_error} attribute was removed.
66 The udev control socket is now created in /run/udev/control
67 and no longer as an abstract namespace one.
69 The rules to create persistent network interface and cdrom link
70 rules automatically in /etc/udev/rules.d/ have been disabled by
71 default. Explicit configuration will be required for these use
72 cases, udev will no longer try to write any persistent system
73 configuration from a device hotplug path.
79 The udev-acl extra is no longer enabled by default now. To enable it,
80 --enable-udev_acl needs to be given at ./configure time. On systemd
81 systems, the udev-acl rules prevent it from running as the functionality
88 Udev now enables kernel media-presence polling if available. Part
89 of udisks optical drive tray-handling moved to cdrom_id: The tray
90 is locked as soon as a media is detected to enable the receiving
91 of media-eject-request events. Media-eject-request events will
94 Libudev enumerate is now able to enumerate a subtree of a given
97 The mobile-action-modeswitch modeswitch tool was deleted. The
98 functionality is provided by usb_modeswitch now.
104 The systemd service files require systemd version 28. The systemd
105 socket activation make it possible now to start 'udevd' and 'udevadm
106 trigger' in parallel.
110 Fix bug in control message handling, which can lead to a failing
111 udevadm control --exit. Thanks to Jürg Billeter for help tracking
118 We require at least Linux kernel 2.6.32 now. Some platforms might
119 require a later kernel that supports accept4() and similar, or
120 need to backport the trivial syscall wiring to the older kernels.
122 The hid2hci tool moved to the bluez package and was removed.
124 Many of the extras can be --enable/--disabled at ./configure
125 time. The --disable-extras option was removed. Some extras have
126 been disabled by default. The current options and their defaults
127 can be checked with './configure --help'.
133 Udev logs a warning now if /run is not writable at udevd
134 startup. It will still fall back to /dev/.udev, but this is
135 now considered a bug.
137 The running udev daemon can now cleanly shut down with:
138 udevadm control --exit
140 Udev in initramfs should clean the state of the udev database
141 with: udevadm info --cleanup-db which will remove all state left
142 behind from events/rules in initramfs. If initramfs uses
143 --cleanup-db and device-mapper/LVM, the rules in initramfs need
144 to add OPTIONS+="db_persist" for all dm devices. This will
145 prevent removal of the udev database for these devices.
147 Spawned programs by PROGRAM/IMPORT/RUN now have a hard timeout of
148 120 seconds per process. If that timeout is reached the spawned
149 process will be killed. The event timeout can be overwritten with
152 If systemd is used, udev gets now activated by netlink data.
153 Systemd will bind the netlink socket which will buffer all data.
154 If needed, such setup allows a seemless update of the udev daemon,
155 where no event can be lost during a udevd update/restart.
156 Packages need to make sure to: systemctl stop udev.socket udev.service
157 or 'mask' udev.service during the upgrade to prevent any unwanted
158 auto-spawning of udevd.
159 This version of udev conflicts with systemd version below 25. The
160 unchanged service files will not wirk correctly.
166 The udev runtime data moved from /dev/.udev/ to /run/udev/. The
167 /run mountpoint is supposed to be a tmpfs mounted during early boot,
168 available and writable to for all tools at any time during bootup,
169 it replaces /var/run/, which should become a symlink some day.
171 If /run does not exist, or is not writable, udev will fall back using
174 On systemd systems with initramfs and LVM used, packagers must
175 make sure, that the systemd and initramfs versions match. The initramfs
176 needs to create the /run mountpoint for udev to store the data, and
177 mount this tmpfs to /run in the rootfs, so the that the udev database
178 is preserved for the udev version started in the rootfs.
180 The command 'udevadm info --convert-db' is gone. The udev daemon
181 itself, at startup, converts any old database version if necessary.
183 The systemd services files have been reorganized. The udev control
184 socket is bound by systemd and passed to the started udev daemon.
185 The udev-settle.service is no longer active by default. Services which
186 can not handle hotplug setups properly need to actively pull it in, to
187 act like a barrier. Alternatively the settle service can be unconditionally
188 'systemctl'enabled, and act like a barrier for basic.target.
190 The fstab_import callout is no longer built or installed. Udev
191 should not be used to mount, does not watch changes to fstab, and
192 should not mirror fstab values in the udev database.
198 New and updated keymaps.
204 The udev database has changed, After installation of a new udev
205 version, 'udevadm info --convert-db' should be called, to let the new
206 udev/libudev version read the already stored data.
208 udevadm now supports quoting of property values, and prefixing of
210 $ udevadm info --export --export-prefix=MY_ --query=property -n sda
213 MY_DEVNAME='/dev/sda'
217 libudev now supports:
218 udev_device_get_is_initialized()
219 udev_enumerate_add_match_is_initialized()
220 to be able to skip devices the kernel has created , but udev has
223 libudev now supports:
224 udev_device_get_usec_since_initialized()
225 to retrieve the "age" of a udev device record.
227 GUdev supports a more generic GUdevEnumerator class, udev TAG
228 handling, device initialization and timestamp now.
230 The counterpart of /sys/dev/{char,block}/$major:$minor,
231 /dev/{char,block}/$major:$minor symlinks are now unconditionally
232 created, even when no rule files exist.
234 New and updated keymaps.
240 GUdev moved from /usr to /.
250 Persistent network naming rules are disabled inside of Qemu/KVM now.
252 New and updated keymaps.
254 Udev gets unconditionally enabled on systemd installations now. There
255 is no longer the need to to run 'systemctl enable udev.service'.
269 New and fixed keymaps.
271 Install systemd service files if applicable.
277 All distribution specific rules are removed from the udev source tree,
278 most of them are no longer needed. The Gentoo rules which allow to support
279 older kernel versions, which are not covered by the default rules anymore
280 has moved to rules/misc/30-kernel-compat.rules.
286 The option --debug-trace and the environemnt variable UDEVD_MAX_CHILDS=
287 was removed from udevd.
289 Udevd now checks the kernel commandline for the following variables:
290 udev.log-priority=<syslog priority>
291 udev.children-max=<maximum number of workers>
292 udev.exec-delay=<seconds to delay the execution of RUN=>
293 to help debuging coldplug setups where the loading of a kernel
294 module crashes the system.
296 The subdirectory in the source tree rules/packages has been renamed to
297 rules/arch, anc contains only architecture specific rules now.
307 Now the udev daemon itself, does on startup:
308 - copy the content of /lib/udev/devices to /dev
309 - create the standard symlinks like /dev/std{in,out,err},
310 /dev/core, /dev/fd, ...
311 - use static node information provided by kernel modules
312 and creates these nodes to allow module on-demand loading
313 - possibly apply permissions to all ststic nodes from udev
314 rules which are annotated to match a static node
316 The default mode for a device node is 0600 now to match the kernel
317 created devtmpfs defaults. If GROUP= is specified and no MODE= is
318 given the default will be 0660.
324 Udev now gradually starts to pass control over the primary device nodes
325 and their names to the kernel, and will in the end only manage the
326 permissions of the node, and possibly create additional symlinks.
327 As a first step NAME="" will be ignored, and NAME= setings with names
328 other than the kernel provided name will result in a logged warning.
329 Kernels that don't provide device names, or devtmpfs is not used, will
330 still work as they did before, but it is strongly recommended to use
331 only the same names for the primary device node as the recent kernel
332 provides for all devices.
336 Fix broken firmware loader search path.
342 "udevadm trigger" defaults to "change" events now instead of "add"
343 events. The "udev boot script" might need to add "--action=add" to
344 the trigger command if not already there, in case the initial coldplug
345 events are expected as "add" events.
347 The option "all_partitons" was removed from udev. This should not be
348 needed for usual hardware. Udev can not safely make assumptions
349 about non-existing partition major/minor numbers, and therefore no
350 longer provide this unreliable and unsafe option.
352 The option "ignore_remove" was removed from udev. With devtmpfs
353 udev passed control over device nodes to the kernel. This option
354 should not be needed, or can not work as advertised. Neither
355 udev nor the kernel will remove device nodes which are copied from
356 the /lib/udev/devices/ directory.
358 All "add|change" matches are replaced by "!remove" in the rules and
359 in the udev logic. All types of events will update possible symlinks
360 and permissions, only "remove" is handled special now.
362 The modem modeswitch extra was removed and the external usb_modeswitch
363 program should be used instead.
365 New and fixed keymaps.
375 Kernels with SYSFS_DEPRECATED=y are not supported since a while. Many users
376 depend on the current sysfs layout and the information not available in the
377 deprecated layout. All remaining support for the deprecated sysfs layout is
382 Fix for a possible endless loop in the new input_id program.
388 The option "ignore_device" does no longer exist. There is no way to
389 ignore an event, as libudev events can not be suppressed by rules.
390 It only prevented RUN keys from being executed, which results in an
391 inconsistent behavior in current setups.
393 BUS=, SYSFS{}=, ID= are long deprecated and should be SUBSYSTEM(S)=,
394 ATTR(S){}=, KERNEL(S)=. It will cause a warning once for every rule
397 The support for the deprecated IDE devices has been removed from the
398 default set of rules. Distros who still care about non-libata drivers
399 need to add the rules to the compat rules file.
401 The ID_CLASS property on input devices has been replaced by the more accurate
402 set of flags ID_INPUT_{KEYBOARD,KEY,MOUSE,TOUCHPAD,TABLET,JOYSTICK}. These are
403 determined by the new "input_id" prober now. Some devices, such as touchpads,
404 can have several classes. So if you previously had custom udev rules which e. g.
405 checked for ENV{ID_CLASS}=="kbd", you need to replace this with
406 ENV{ID_INPUT_KEYBOARD}=="?*".
412 To support DEVPATH strings larger than the maximum file name length, the
413 private udev database format has changed. If some software still reads the
414 private files in /dev/.udev/, which it shouldn't, now it's time to fix it.
415 Please do not port anything to the new format again, everything in /dev/.udev
416 is and always was private to udev, and may and will change any time without
419 Multiple devices claiming the same names in /dev are limited to symlinks
420 only now. Mixing identical symlink names and node names is not supported.
421 This reduces the amount of data in the database significantly.
423 NAME="%k" causes a warning now. It's is and always was completely superfluous.
424 It will break kernel supplied DEVNAMEs and therefore it needs to be removed
427 Most NAME= instructions got removed. Kernel 2.6.31 supplies the needed names
428 if they are not the default. To support older kernels, the NAME= rules need to
429 be added to the compat rules file.
431 Symlinks to udevadm with the old command names are no longer resolved to
432 the udevadm commands.
434 The udev-acl tool got adopted to changes in ConsoleKit. Version 0.4.1 is
437 The option "last_rule" does no longer exist. Its use breaks too many
438 things which expect to be run from independent later rules, and is an idication
439 that something needs to be fixed properly instead.
441 The gudev API is no longer marked as experimental,
442 G_UDEV_API_IS_SUBJECT_TO_CHANGE is no longer needed. The gudev introspection
443 is enabled by default now. Various projects already depend on introspection
444 information to bind dynamic languages to the gudev interfaces.
450 The udevadm trigger "--retry-failed" option, which is replaced since quite
451 a while by "--type=failed" is removed.
453 The failed tracking was not working at all for a few releases. The RUN
454 option "ignore_error" is replaced by a "fail_event_on_error" option, and the
455 default is not to track any failing RUN executions.
457 New keymaps, new modem, hid2hci updated.
461 Fix possible crash in udevd when worker processes are busy, rules are
462 changed at the same time, and workers get killed to reload the rules.
468 Properties set with ENV{.FOO}="bar" are marked private by starting the
469 name with a '.'. They will not be stored in the database, and not be
470 exported with the event.
472 Firmware files are looked up in:
473 /lib/firmware/updates/$(uname -r)
474 /lib/firmware/updates
475 /lib/firmware/$(uname -r)
479 ATA devices switched the property from ID_BUS=scsi to ID_BUS=ata.
480 ata_id, instead of scsi_id, is the default tool now for ATA devices.
486 The configure options have changed because another library needs to be
487 installed in a different location. Instead of exec_prefix and udev_prefix,
488 libdir, rootlibdir and libexecdir are used. The Details are explained in
491 Event processes now get re-used after they handled an event. This reduces
492 the number of forks and the pressure on the CPU significantly, because
493 cloned event processes no longer cause page faults in the main daemon.
494 After the events have settled, a few worker processes stay around for
495 future events, all others get cleaned up.
497 To be able to use signalfd(), udev depends on kernel version 2.6.25 now.
498 Also inotify support is mandatory now to run udev.
500 The format of the queue exported by the udev damon has changed. There is
501 no longer a /dev/.udev/queue/ directory. The current event queue can be
502 accessed with udevadm settle and libudedv.
504 Libudev does not have the unstable API header anymore. From now on,
505 incompatible changes will be handled by bumping the library major version.
507 To build udev from the git tree gtk-doc is needed now. The tarballs will
508 build without it and contain the pre-built documentation. An online copy
510 http://www.kernel.org/pub/linux/utils/kernel/hotplug/libudev/
512 The tools from the udev-extras repository have been merged into the main
513 udev repository. Some of the extras have larger external dependencies, and
514 they can be disabled with the configure switch --disable-extras.
520 The program vol_id and the library libvolume_id are removed from the
521 repository. Libvolume_id is merged with libblkid from the util-linux-ng
522 package. Persistent disk links for label and uuid depend on the
523 util-linux-ng version (2.15) of blkid now. Older versions of blkid
524 can not be used with udev.
526 Libudev allows to subscribe to udev events. To prevent unwanted messages
527 to be delivered, and waking up the subscribing process, a filter can be
528 installed, to drop messages inside a kernel socket filter. The filters
529 match on the <subsytem>:<devtype> properties of the device.
530 This is part of the ongoing effort to replace HAL, and switch current
531 users over to directly use libudev.
532 Libudev is still marked as experimental, and its interface might
533 eventually change if needed, but no major changes of the currently exported
534 interface are expected anymore, and a first stable release should happen
537 A too old kernel (2.6.21) or a kernel with CONFIG_SYSFS_DEPRECATED
538 is not supported since while and udevd will log an error message at
539 startup. It should still be able to boot-up, but advanced rules and system
540 services which depend on the information not available in the old sysfs
541 format will fail to work correctly.
543 DVB device naming is supplied by the kernel now. In case older kernels
544 need to be supported, the old shell script should be added to a compat
551 The processed udev events get send back to the netlink socket. Libudev
552 provides access to these events. This is work-in-progress, to replace
553 the DeviceKit daemon functionality directly with libudev. There are
554 upcoming kernel changes to allow non-root users to subcribe to these
561 "udevadm settle" now optionally accepts a range of events to wait for,
562 instead of waiting for "all" events.
568 The installed watch for block device metadata changes is now removed
569 during event hadling, because some (broken) tools may be called from udev
570 rules and (wrongly) open the device with write access. After the finished
571 event handling the watch is restored.
577 Device nodes can be watched for changes with inotify with OPTIONS="watch".
578 If closed after being opened for writing, a "change" uevent will occur.
579 /dev/disk/by-{label,uuid}/* symlinks will be automatically updated.
585 The udevadm test command has no longer a --force option, nodes and symlinks
586 are always updated with a test run now.
588 The udevd daemon can be started with --resolve-names=never to avoid all user
589 and group lookups (e.g. in cut-down systems) or --resolve-names=late to
590 lookup user and groups every time events are handled.
596 We are currently merging the Ubuntu rules in the udev default rules,
597 and get one step closer to provide a common Linux /dev setup, regarding
598 device names, symlinks, and default device permissions. On udev startup,
599 we now expect the following groups to be resolvable to their ids with
601 disk, cdrom, floppy, tape, audio, video, lp, tty, dialout, kmem.
602 LDAP setups need to make sure, that these groups are always resolvable at
603 bootup, with only the rootfs mounted, and without network access available.
605 Some systems may need to add some new, currently not used groups, or need
606 to add some users to new groups, but the cost of this change is minimal,
607 compared to the pain the current, rather random, differences between the
608 various distributions cause for upstream projects and third-party vendors.
610 In general, "normal" users who log into a machine should never be a member
611 of any such group, but the device-access should be managed by dynamic ACLs,
612 which get added and removed for the specific users on login/logout and
613 session activity/inactivity. These groups are only provided for custom setups,
614 and mainly system services, to allow proper privilege separation.
615 A video-streaming daemon uid would be a member of "audio" and "video", to get
616 access to the sound and video devices, but no "normal" user should ever belong
617 to the "audio" group, because he could listen to the built-in microphone with
618 any ssh-session established from the other side of the world.
620 /dev/serial/by-{id,path}/ now contains links for ttyUSB devices,
621 which do not depend on the kernel device name. As usual, unique
622 devices - only a single one per product connected, or a real
623 USB serial number in the device - are always found with the same
624 name in the by-id/ directory.
625 Completely identical devices may overwrite their names in by-id/
626 and can only be found reliably in the by-path/ directory. Devices
627 specified by by-path/ must not change their connection, like the
628 USB port number they are plugged in, to keep their name.
630 To support some advanced features, Linux 2.6.22 is the oldest supported
631 version now. The kernel config with enabled SYSFS_DEPRECATED is no longer
632 supported. Older kernels should still work, and devices nodes should be
633 reliably created, but some rules and libudev will not work correctly because
634 the old kernels do not provide the expected information or interfaces.
640 Fix for a possible segfault while swapping network interface names in udev
647 The group "video" is part of the default rules now.
651 Bugfix for kernels using SYSFS_DEPRECATED* option and finding parent
652 block devices in some cases. No common distro uses this option anymore,
653 and we do not get enough testing for this and recent udev versions. If
654 this option is not needed to run some old distro with a new kernel,
655 it should be disabled in the kernel config.
657 Bugfix for the $links substitution variable, which may crash if no links
658 are created. This should not happen in usual setups because we always
659 create /dev/{block,char}/ links.
661 The strings of the parsed rules, which are kept in memory, no longer
662 contain duplicate entries, or duplicate tails of strings. This, and the
663 new rules parsing/matching code reduces the total in-memory size of
664 a huge distro rule sets to 0.08 MB, compared to the 1.2MB of udev
667 The export of DEVTYPE=disk/partition got removed from the default
668 rules. This value is available from the kernel. The pnp shell script
669 modprobe hack is removed from the default rules. ACPI devices have _proper_
670 modalias support and take care of the same functionality.
671 Installations which support old kernels, but install current default
672 udev rules may want to add that to the compat rules file.
674 Libvolume_id now always probes for all known filesystems, and does not
675 stop at the first match. Some filesystems are marked as "exclusive probe",
676 and if any other filesytem type matches at the same time, libvolume_id
677 will, by default, not return any probing result. This is intended to prevent
678 mis-detection with conflicting left-over signatures found from earlier
679 file system formats. That way, we no longer depend on the probe-order
680 in case of multiple competing signatures. In some setups the kernel allows
681 to mount a volume with just the old filesystem signature still in place.
682 This may damage the new filesystem and cause data-loss, just by mounting
683 it. Because volume_id can not decide which one the correct signature is,
684 the wrong signatures need to be removed manually from the volume, or the
685 volume needs to be reformatted, to enable filesystem detection and possible
690 Fix segfault if compiled without optimization and dbg() does not get
691 compiled out and uses variables which are not available.
695 Bugfixes. (And maybe new bugs. :))
697 The rule matching engine got converted from a rule list to a token
698 array which reduced the in-memory rules representation of a full
699 featured distros with thousends of udev rules from 1.2MB to 0.12 MB.
700 Limits like 5 ENV and ATTR matches, and one single instance for most
701 other keys per rule are gone.
703 The NAME assignment is no longer special cased. If later rules assign
704 a NAME value again, the former value will be overwritten. As usual
705 for most other keys, the NAME value can be protected by doing a final
706 assignment with NAME:="<value>".
708 All udev code now uses libudev, which is also exported. The library
709 is still under development, marked as experimental, and its interface
710 may change as long as the DeviceKit integration is not finished.
712 Many thanks to Alan Jenkins for his continuous help, and finding and
713 optimizing some of the computing expensive parts.
719 Kernel devices and device nodes are connected now by reverse indizes in
720 /sys and /dev. A device number retrieved by a stat() or similar, the
721 kernel device directory can be found by looking up:
722 /sys/dev/{block,char}/<maj>:<min>
723 and the device node of the same device by looking up:
724 /dev/{block,char}/<maj>:<min>
728 Fix recently introduced bug, which caused a compilation without large
729 file support, where vol_id does not recognize raid signatures at the end
732 Firewire disks now create both, by-id/scsi-* and by-id/ieee-* links.
733 Seems some kernel versions prevent the creation of the ieee-* links,
734 so people used the scsi-* link which disappeared now.
736 More libudev work. Almost all udevadm functionality comes from libudev
739 udevadm trigger has a new option --type, which allows to trigger events
740 for "devices", for "subsystems", or "failed" devices. The old option
741 --retry-failed" still works, but is no longer mentioned in the man page.
747 The udevadm info --device-id-of-file= output has changed to use
748 the obvious format. Possible current users should use the --export
749 option which is not affected.
751 The old udev commands symlinks to udevadm are not installed, if
752 these symlinks are used, a warning is printed.
758 Optical drive's media is no longer probed for raid signatures,
759 reading the end of the device causes some devices to malfunction.
760 Also the offset of the last session found is used now to probe
763 The volume_id library got a major version number update to 1,
764 some deprecated functions are removed.
766 A shared library "libudev" gets installed now to provide access
767 to udev device information. DeviceKit, the successor of HAL, will
768 need this library to access the udev database and search sysfs for
770 The library is currently in an experimental state, also the API is
771 expected to change, as long as the DeviceKit integration is not
776 We use ./configure now. See INSTALL for details. Current
779 "/usr" - prefix for man pages, include files
781 "" - the root filesystem, prefix for libs and binaries
785 "lib" - directory name for libraries, not a path name
786 multilib 64bit systems may use "lib64" instead of "lib"
788 compile-in verbose debug messages
790 disable all logging and compile-out all log strings
792 link against SELInux libraries, to set the expected context
795 In the default rules, the group "disk" gets permissions 0660 instead
796 of 0640. One small step closer to unify distro rules. Some day, all
797 distros hopefully end up with the same set of rules.
799 No symlinks to udevadm are installed anymore, if they are still needed,
800 they should be provided by the package.
806 Default udev rules, which are not supposed to be edited by the user, should
807 be placed in /lib/udev/rules.d/ now, to make it clear that they are private to
808 the udev package and will be replaced with an update. Udev will pick up rule
810 /lib/udev/rules.d/ - default installed rules
811 /etc/udev/rules.d/ - user rules + on-the-fly generated rules
812 /dev/.udev/rules.d/ - temporary non-persistent rules created after bootup
813 It does not matter in which directory a rule file lives, all files are sorted
816 To help creating /dev/root, we have now:
817 $ udevadm info --export --export-prefix="ROOT_" --device-id-of-file=/
820 In case the current --device-id-of-file is already used, please switch to
821 the --export format version, it saves the output parsing and the old
822 format will be changed to use ':' as a separator, like the format in the
827 Fix cdrom_id to properly recognize blank media.
833 Tape drive id-data is queried from /dev/bsg/* instead of the tape
834 nodes. This avoids rewinding tapes on open().
840 The symlinks udevcontrol and udevtrigger are no longer installed by
843 The scsi_id program does not depend on sysfs anymore. It can speak
844 SGv4 now, so /dev/bsg/* device nodes can be used, to query SCSI device
845 data, which should solve some old problems with tape devices, where
846 we better do not open all tape device nodes to identify the device.
852 The cdrom_id program is replaced by an advanced version, which can
853 detect most common device types, and also properties of the inserted
854 media. This is part of moving some basic functionality from HAL into
855 udev (and the kernel).
861 The last WAIT_FOR_SYSFS rule is removed from the default rules.
863 The symlinks to udevadm for the debugging tools: udevmonitor and
864 udevtest are no longer created.
866 The symlinks to the udevadm man page for the old tool names are
869 Abstract namespace sockets paths in RUN+="socket:@<path>" rules,
870 should be prefixed with '@' to indicate that the path is not a
881 Udevstart is removed from the tree, it did not get installed for
882 a long time now, and is long replaced by trigger and settle.
888 All udev tools are merged into a single binary called udevadm.
889 The old names of the tools are built-in commands in udevadm now.
890 Symlinks to udevadm, with the names of the old tools, provide
891 the same functionality as the standalone tools. There is also
892 only a single udevadm.8 man page left for all tools.
894 Tools like mkinitramfs should be checked, if they need to include
895 udevadm in the list of files.
905 The etc/udev/rules.d/ directory now contains a default set of basic
906 udev rules. This initial version is the result of a rules file merge
907 of Fedora and openSUSE. For these both distros only a few specific
908 rules are left in their own file, named after the distro. Rules which
909 are optionally installed, because they are only valid for a specific
910 architecture, or rules for subsystems which are not always used are
911 in etc/udev/packages/.
917 Dynamic rules can be created in /dev/.udev/rules.d/ to trigger
918 actions by dynamically created rules.
920 SYMLINK=="<value>" matches agains the entries in the list of
921 currently defined symlinks. The links are not created in the
922 filesystem at that point in time, but the values can be matched.
924 RUN{ignore_error}+="<program>" will ignore any exit code from the
925 program and not record as a failed event.
931 Final merge of patches/features from the Ubuntu package.
937 Control characters in filesystem label strings are no longer silenty
938 removed, but hex-encoded, to be able to uniquely identify the device
939 by its symlink in /dev/disk/by-label/.
940 If libvolume_id is used by mount(8), LABEL= will work as expected,
941 if slashes or other characters are used in the label string.
943 To test the existence of a file, TEST=="<file>" and TEST!="<file>"
944 can be specified now. The TEST key accepts an optional mode mask
945 TEST{0100}=="<is executable file>".
947 Scsi_id now supports a mode without expecting scsi-specific sysfs
948 entries to allow the extraction of cciss-device persistent properties.
954 In the future, we may see uuid's which are just simple character
955 strings (see the DDF Raid Specification). For that reason vol_id now
956 exports ID_FS_UUID_SAFE, just like ID_FS_LABEL_SAFE. For things like
957 the creation of symlinks, the *_SAFE values ensure, that no control
958 or whitespace characters are used in the filename.
960 Possible users of libvolume_id, please use the volume_id_get_* functions.
961 The public struct will go away in a future release of the library.
967 Removal of useless extras/eventrecorder.sh.
977 The directory multiplexer for dev.d/ and hotplug.d are finally removed
978 from the udev package.
984 Symlinks can have priorities now, the priority is assigned to the device
985 and specified with OPTIONS="link_priority=100". Devices with higher
986 priorities overwrite the symlinks of devices with lower priorities.
987 If the device that currently owns the link, goes away, the symlink
988 will be removed, and recreated, pointing to the next device with the
989 highest actual priority. This should make /dev/disk/by-{label,uuid,id}
990 more reliable, if multiple devices contain the same metadata and overwrite
993 The dasd_id program is removed from the udev tree, and dasdinfo, with the
994 needed rules, are part of the s390-tools now.
996 Please add KERNEL=="[0-9]*:[0-9]*" to the scsi wait-for-sysfs rule,
997 we may get the scsi sysfs mess fixed some day, and this will only catch
998 the devices we are looking for.
1000 USB serial numbers for storage devices have the target:lun now appended,
1001 to make it possibble to distinguish broken multi-lun devices with all
1002 the same SCSI identifiers.
1004 Note: The extra "run_directory" which searches and executes stuff in
1005 /etc/hotplug.d/ and /etc/dev.d/ is long deprecated, and will be removed
1006 with the next release. Make sure, that you don't use it anymore, or
1007 provides your own implementation of that inefficient stuff.
1008 We are tired of reports about a "slow udev", because these directories
1009 contain stuff, that runs with _every_ event, instead of using rules,
1010 that run programs only for the matching events.
1020 DRIVER== will match only for devices that actually have a real
1021 driver. DRIVERS== must be used, if parent devices should be
1022 included in the match.
1024 Libvolume_id's "linux_raid" detection needed another fix.
1032 Add additional check to volume_id detection of via_raid, cause
1033 some company decided to put a matching pattern all over the empty
1034 storage area of their music players.
1038 Fix path_id for SAS devices.
1042 The udev daemon can be started with --debug-trace now, which will
1043 execute all events serialized to get a chance to catch a possible
1044 action that crashes the box.
1046 A warning is logged, if PHYSDEV* keys, the "device" link, or a parent
1047 device attribute like $attr{../file} is used, only WAIT_FOR_SYSFS rules
1048 are excluded from the warning. Referencing parent attributes directly
1049 may break when something in the kernel driver model changes. Udev will
1050 just find the attribute by walking up the parent chain.
1052 Udevtrigger now sorts the list of devices depending on the device
1053 dependency, so a "usb" device is triggered after the parent "pci"
1058 Revert persistent-storage ata-serial '_' '-' replacement.
1064 Udevtrigger can now filter the list of devices to be triggered. Matches
1065 for subsystems or sysfs attributes can be specified.
1067 The entries in /dev/.udev/queue and /dev/.udev/failed have changed to
1068 zero-sized files to avoid pointing to /sys and confuse broken tools which
1069 scan the /dev directory. To retry failed events, udevtrigger --retry-failed
1072 The rules and scripts to create udev rules for persistent network
1073 devices and optical drives are in the extras/rules_generator directory
1074 now. If you use something similar, please consider replacing your own
1075 version with this, to share the support effort. The rule_generator
1076 installs its own rules into /etc/udev/rules.d.
1078 The cdrom_id tool installs its own rule now in /etc/udev/rules.d, cause
1079 the rule_generator depends on cdrom_id to be called in an earlier rule.
1085 Renaming of some key names (the old names still work):
1086 BUS -> SUBSYSTEMS, ID -> KERNELS, SYSFS -> ATTRS, DRIVER -> DRIVERS.
1087 (The behavior of the key DRIVER will change soon in one of the next
1088 releases, to match only the event device, please switch to DRIVERS
1089 instead. If DRIVER is used, it will behave like DRIVERS, but an error
1091 With the new key names, we have a more consistent and simpler scheme.
1092 We can match the properties of the event device only, with: KERNEL,
1093 SUBSYSTEM, ATTR, DRIVER. Or include all the parent devices in the match,
1094 with: KERNELS, SUBSYSTEMS, ATTRS, DRIVERS. ID, BUS, SYSFS, DRIVER are no
1095 longer mentioned in the man page and should be switched in the rule
1098 ATTR{file}="value" can be used now, to write to a sysfs file of the
1099 event device. Instead of:
1100 ..., SYSFS{type}=="0|7|14", RUN+="/bin/sh -c 'echo 60 > /sys$$DEVPATH/timeout'"
1102 ..., ATTR{type}=="0|7|14", ATTR{timeout}="60"
1104 All the PHYSDEV* keys are deprecated and will be removed from a
1106 PHYDEVPATH - is the path of a parent device and should not be
1108 PHYSDEVBUS - is just a SUBSYSTEM value of a parent, and can be
1109 matched with SUBSYSTEMS==
1110 PHYSDEVDRIVER - for bus devices it is available as ENV{DRIVER}.
1111 Newer kernels will have DRIVER in the environment,
1112 for older kernels udev puts in. Class device will
1113 no longer carry this property of a parent and
1114 DRIVERS== can be used to match such a parent value.
1115 Note that ENV{DRIVER} is only available for a few bus devices, where
1116 the driver is already bound at device event time. On coldplug, the
1117 events for a lot devices are already bound to a driver, and they will have
1118 that value set. But on hotplug, at the time the kernel creates the device,
1119 it can't know what driver may claim the device after that, therefore
1120 in most cases it will be empty.
1122 Failed events should now be re-triggered with:
1123 udevtrigger --retry-failed.
1124 Please switch to this command, so we keep the details of the /dev/.udev/failed/
1125 files private to the udev tools. We may need to switch the current symlink
1126 target, cause some obviously broken tools try to scan all files in /dev
1127 including /dev/.udev/, find the links to /sys and end up stat()'ing sysfs files
1128 million times. This takes ages on slow boxes.
1130 The udevinfo attribute walk (-a) now works with giving a device node
1131 name (-n) instead of a devpath (-p). The query now always works, also when
1132 no database file was created by udev.
1134 The built-in /etc/passwd /etc/group parser is removed, we always depend on
1135 getpwnam() and getgrnam() now. One of the next releases will depend on
1136 fnmatch() and may use getopt_long().
1140 Bugfixes and small improvements.
1144 Fix path_id for recent kernels.
1150 Added support for swapping network interface names, by temporarily
1151 renaming the device and wait for the target name to become free.
1155 The built-in MODALIAS key and substitution is removed.
1159 The binary firmware helper is replaced by the usual simple
1160 shell script. Udevsend is removed from the tree.
1168 Some more keys require the correct use of '==' and '=' depending
1169 on the kind of operation beeing an assignment or a match. Rules
1170 with invalid operations are skipped and logged to syslog. Please
1171 test with udevtest if the parsing of your rules throws errors and
1172 fix possibly broken rules.
1176 Provide "udevsettle" to wait for all current udev events to finish.
1177 It also watches the current kernel netlink queue by comparing the
1178 even sequence number to make sure that there are no current pending
1179 events that have not already arrived in the daemon.
1183 Fix rule to skip persistent rules for removable IDE devices, which
1184 also skipped optical IDE drives.
1186 All *_id program are installed in /lib/udev/ by default now.
1188 No binary is stripped anymore as this should be done in the
1189 packaging process and not at build time.
1191 libvolume_id is provided as a shared library now and vol_id is
1192 linked against it. Also one of the next HAL versions will require
1193 this library, and the HAL build process will also require the
1194 header file to be installed. The copy of the same code in HAL will
1195 be removed to have only a single copy left on the system.
1199 Add persistent links for SCSI tapes. The rules file is renamed
1200 to 60-persistent-storage.rules.
1202 Create persistent path for usb devices. Can be used for all sorts
1203 of devices that can't be distinguished by other properties like
1204 multiple identical keyboards and mice connected to the same box.
1206 Provide "udevtrigger" program to request events on coldplug. The
1207 shell script is much too slow with thousends of devices.
1211 Fix persistent disk rules to exclude removable IDE drives.
1213 Warn if %e, $modalias or MODALIAS is used.
1217 Fix queue export, which wasn't correct for subsequent add/remove
1218 events for the same device.
1222 Fix cramfs detection on big endian.
1224 Make WAIT_FOR_SYSFS usable in "normal" rules and silent if the whole
1229 If BUS== and SYSFS{}== have been used in the same rule, the sysfs
1230 attributes were only checked at the parent device that matched the
1231 by BUS requested subsystem. Fix it to also look at the device we
1232 received the event for.
1234 Build variable CROSS has changed to CROSS_COMPILE to match the kernel
1239 Fix a bug where NAME="" would prevent RUN from beeing executed.
1241 RUN="/bin/program" does not longer automatically add the subsystem
1242 as the first parameter. This is from the days of /sbin/hotplug
1243 which is dead now and it's just confusing to need to add a space at
1244 the end of the program name to prevent this.
1245 If you use rules that need the subsystem as the first parameter,
1246 like the old "udev_run_hotlugd" and "udev_run_devd", add the subsystem
1247 to the key like RUN+="/bin/program $env{SUBSYSTEM}".
1251 The udev man page has moved to udev(7) as it does not describe a command
1252 anymore. The programs udev, udevstart and udevsend are no longer installed
1253 by default and must be copied manually, if they should be installed or
1254 included in a package.
1256 Fix a bug where "ignore_device" could run earlier collected RUN keys before
1257 the ignore rule was applied.
1259 More preparation for future sysfs changes. usb_id and scsi_id no longer
1260 depend on a magic order of devices in the /devices chain. Specific devices
1261 should be requested by their subsytem.
1263 This will always find the scsi parent device without depending on a specific
1265 dev = sysfs_device_get(devpath);
1266 dev_usb = sysfs_device_get_parent_with_subsystem(dev, "scsi");
1268 The "device" link in the current sysfs layout will be automatically
1269 _resolved_ as a parent and in the new sysfs layout it will just _be_ the
1270 parent in the devpath. If a device is requested by it's symlink, like all
1271 class devices in the new sysfs layout will look like, it gets automatically
1272 resolved and substituted with the real devpath and not the symlink path.
1275 A similar logic must be applied to _all_ sysfs users, including
1276 scripts, that search along parent devices in sysfs. The explicit use of
1277 the "device" link must be avoided. With the future sysfs layout all
1278 DEVPATH's will start with /devices/ and have a "subsystem" symlink poiting
1279 back to the "class" or the "bus". The layout of the parent devices in
1280 /devices is not necessarily expected to be stable across kernel releases and
1281 searching for parents by their subsystem should make sysfs users tolerant
1282 for changed parent chains.
1286 Prepare udev to work with the experimental kernel patch, that moves
1287 /sys/class devices to /sys/devices and /sys/block to /sys/class/block.
1289 Clarify BUS, ID, $id usage and fix $id behavior. This prepares for
1290 moving the class devices to /sys/devices.
1292 Thanks again to Marco for help finding a hopefully nice compromise
1293 to make %b simpler and working again.
1297 Complete removal of libsysfs, replaced by simple helper functions
1298 which are much simpler and a bit faster. The udev daemon operatesentirely
1299 on event parameters and does not use sysfs for simple rules anymore.
1300 Please report any new bugs/problems, that may be caused by this big
1301 change. They will be fixed immediately.
1303 The enumeration format character '%e' is deprecated and will be
1304 removed sometimes from a future udev version. It never worked correctly
1305 outside of udevstart, so we can't use it with the new parallel
1306 coldplug. A simple enumeration is as useless as the devfs naming
1307 scheme, just get rid of both if you still use it.
1309 MODALIAS and $modalias is not needed and will be removed from one of
1310 the next udev versions, replace it in all rules with ENV{MODALIAS} or
1311 the sysfs "modalias" value.
1313 Thanks a lot to Marco for all his help on finding and fixing bugs.
1317 Let scsi_id request libata drive serial numbers from page 0x80.
1319 Renamed etc/udev/persistent.rules to persistent-disk.rules and
1320 added /dev/disk/by-name/* for device mapper device names.
1322 Removed %e from the man page. It never worked reliably outside
1323 of udevstart and udevstart is no longer recommended to use.
1327 Symlinks are now exported to the event environment. Hopefully it's no
1328 longer needed to run udevinfo from an event process, like it was
1329 mentioned on the hotplug list:
1330 UDEV [1134776873.702967] add@/block/sdb
1333 DEVLINKS=/dev/disk/by-id/usb-IBM_Memory_Key_0218B301030027E8 /dev/disk/by-path/usb-0218B301030027E8:0:0:0
1337 Fix a problem if udevsend is used as the hotplug handler and tries to use
1338 syslog, which causes a "vc" event loop. 2.6.15 will make udevsend obsolete
1339 and this kind of problems will hopefully go away soon.
1343 All built-in logic to work around bad sysfs timing is removed with this
1344 version. The need to wait for sysfs files is almost fixed with a kernel
1345 version that doesn't work with this udev version anyway. Until we fix
1346 the timing of the "bus" link creation, the former integrated logic should
1347 be emulated by a rule placed before all other rules:
1348 ACTION=="add", DEVPATH=="/devices/*", ENV{PHYSDEVBUS}=="?*", WAIT_FOR_SYSFS="bus"
1350 The option "udev_db" does no longer exist. All udev state will be in
1351 /$udev_root/.udev/ now, there is no longer an option to set this
1353 If the init script or something else used this value, just depend on
1354 this hardcoded path. But remember _all_content_ of this directory is
1355 still private to udev and can change at any time.
1357 Default location for rule sripts and helper programs is now: /lib/udev/.
1358 Everything that is not useful on the commandline should go into this
1359 directory. Some of the helpers in the extras folder are installed there
1360 now. The rules need to be changed, to find the helpers there.
1362 Also /lib/udev/devices is recommended as a directory where packages or
1363 the user can place real device nodes, which get copied over to /dev at
1364 every boot. This should replace the various solutions with custom config
1367 Udevsend does no longer start the udev daemon. This must be done with
1368 the init script that prepares /dev on tmpfs and creates the initial nodes,
1369 before starting the daemon.
1373 Silent a too verbose error logging for the old hotplug.d/ dev.d/
1376 The copy of klibc is removed. A systemwide installed version of klibc
1377 should be used to build a klibc udev now.
1381 NAME="" will not create any nodes, but execute RUN keys. To completely
1382 ignore an event the OPTION "ignore_device" should be used.
1384 After removal of the reorder queue, events with a TIMEOUT can be executed
1385 without any queuing now.
1389 Fixed bug in udevd, if inotify is not available. We depend on netlink
1390 uevents now, kernels without that event source will not work with that
1391 version of udev anymore.
1395 The rule parsing happens now in the daemon once at startup, all udev
1396 event processes inherit the already parsed rules from the daemon.
1397 It is shipped with SUSE10.0 and reduces heavily the system load at
1398 startup. The option to save precompiled rules and let the udev process
1399 pick the them up is removed, as it's no longer needed.
1401 Kernel 2.6.15 will have symlinks at /class/input pointing to the real
1402 device. Libsysfs is changed to "translate" the requested link into the
1403 real device path, as it would happen with the hotplug event. Otherwise
1404 device removal and the udev database will not work.
1406 Using 'make STRIPCMD=' will leave the binaries unstripped for debugging
1409 A few improvements for vol_id, the filesytem probing code.
1413 Fix a stupid typo in extras/run_directory for "make install".
1415 scsi_id creates the temporary devnode now in /dev for usage with a
1416 non-writable /tmp directory.
1418 The uevent kernel socket buffer can carry app. 50.000 events now,
1419 let's see who can break this again. :)
1421 The upcoming kernel will have a new input driver core integration.
1422 Some class devices are now symlinks to the real device. libsysfs
1423 needs a fix for this to work correctly. Udevstart of older udev
1424 versions will _not_ create these devices!
1428 Fix a 'install' target in the Makefile, that prevents EXTRAS from
1433 A bunch of mostly trivial bugfixes. From now on no node name or
1434 symlink name can contain any character than plain whitelisted ascii
1435 characters or validated utf8 byte-streams. This is needed for the
1436 /dev/disk/by-label/* links, because we import untrusted data and
1437 export it to the filesystem.
1441 More bugfixes. If udevd was started from the kernel, we don't
1442 have stdin/stdout/stderr, which broke the forked tools in some
1447 Bugfix. udevstart event ordering was broken for a long time.
1448 The new run_program() uncovered it, because /dev/null was not
1449 available while we try to run external programs.
1450 Now udevstart should create it before we run anything.
1454 Minor bugfixes and some distro rules updates. If you don't have the
1455 persistent disk rules in /dev/disk/by-*/* on your distro, just
1456 grab it from here. :)
1460 We can use socket communication now to pass events from udev to
1462 RUN+="socket:/org/freedesktop/hal/udev_event"
1463 will pass the whole udev event to the HAL daemon without the need
1464 for a forked helper. (See ChangeLog for udevmonitor, as an example)
1468 Mostly bugfixes and see ChangeLog.
1470 The test for the existence of an environment value should be
1472 ENV{KEY}=="*" to ENV{KEY}=="?*"
1473 because "*" will not fail anymore, if the key does not exist or
1478 Bugfixes and a few tweaks described in the ChangeLog.
1482 Mostly a Bugfix release.
1484 Added WAIT_FOR_SYSFS="<attribute>" to be able to fight against the sysfs
1485 timing with custom rules.
1489 We changed the internal rule storage format. Our large rule files took
1490 2 MB of RAM, with the change we are down to 99kB.
1492 If the device-node has been created with default name and no symlink or
1493 options are to remenber, it is not longer stored in the udevdb. HAL will
1494 need to be updated to work correctly with that change.
1496 To overrride optimization flags, OPTFLAGS may be used now.
1504 Major changes happened with this release. The goal is to take over the
1505 complete kernel-event handling and provide a more efficient way to dispatch
1506 kernel events. Replacing most of the current shell script logic and the
1507 kernel forked helper with a netlink-daemon and a rule-based event handling.
1509 o udevd listens to netlink events now. The first valid netlink event
1510 will make udevd ignore any message from udevsend that contains a
1511 SEQNUM, to avoid duplicate events. The forked events can be disabled
1513 echo "" > /proc/sys/kernel/hotplug
1514 For full support, the broken input-subsytem needs to be fixed, not to
1515 bypass the driver core.
1517 o /etc/dev.d/ + /etc/hotplug.d/ directory multiplexing is completely
1518 removed from udev itself and must be emulated by calling small
1519 helper binaries provided in the extras folder:
1520 make EXTRAS=extras/run_directory/
1521 will build udev_run_devd and udev_run_hotplugd, which can be called
1522 from a rule if needed:
1523 RUN+="/sbin/udev_run_hotplugd"
1524 The recommended way to handle this is to convert all the calls from
1525 the directories to explicit udev rules and get completely rid of the
1526 multiplexing. (To catch a ttyUSB event, you now no longer need to
1527 fork and exit 300 tty script instances you are not interested in, it
1528 is just one rule that matches exactly the device.)
1530 o udev handles now _all_ events not just events for class and block
1531 devices, this way it is possible to control the complete event
1532 behavior with udev rules. Especially useful for rules like:
1533 ACTION="add", DEVPATH="/devices/*", MODALIAS=="?*", RUN+="/sbin/modprobe $modalias"
1535 o As used in the modalias rule, udev supports now textual
1536 substitution placeholder along with the usual format chars. This
1537 needs to be documented, for now it's only visible in udev_rules_parse.c.
1539 o The rule keys support now more operations. This is documented in the
1540 man page. It is possible to add values to list-keys like the SYMLINK
1541 and RUN list with KEY+="value" and to clear the list by assigning KEY="".
1542 Also "final"-assignments are supported by using KEY:="value", which will
1543 prevent changing the key by any later rule.
1545 o kernel 2.6.12 has the "detached_state" attribute removed from
1546 sysfs, which was used to recognize sysfs population. We switched that
1547 to wait for the "bus" link, which is only available in kernels after 2.6.11.
1548 Running this udev version on older kernels may cause a short delay for
1551 o To provide infrastructure for persistent device naming, the id programs:
1552 scsi_id, vol_id (former udev_volume_id), and ata_id (new) are able now
1553 to export the probed data in environment key format:
1554 pim:~ # /sbin/ata_id --export /dev/hda
1555 ID_MODEL=HTS726060M9AT00
1556 ID_SERIAL=MRH401M4G6UM9B
1557 ID_REVISION=MH4OA6BA
1559 The following rules:
1560 KERNEL="hd*[!0-9]", IMPORT="/sbin/ata_id --export $tempnode"
1561 KERNEL="hd*[!0-9]", ENV{ID_SERIAL}=="?*", SYMLINK+="disk/by-id/$env{ID_MODEL}_$env{ID_SERIAL}"
1564 kay@pim:~> tree /dev/disk
1567 | |-- HTS726060M9AT00_MRH401M4G6UM9B -> ../../hda
1568 | `-- IBM-Memory_Key -> ../../sda
1570 | |-- swap -> ../../hda1
1571 | |-- date -> ../../sda1
1572 | `-- home -> ../../hda3
1574 |-- 2E08712B0870F2E7 -> ../../hda3
1575 |-- 9352cfef-7687-47bc-a2a3-34cf136f72e1 -> ../../hda1
1576 |-- E845-7A89 -> ../../sda1
1577 `-- b2a61681-3812-4f13-a4ff-920d70604299 -> ../../hda2
1579 The IMPORT= operation will import these keys in the environment and make
1580 it available for later PROGRAM= and RUN= executed programs. The keys are
1581 also stored in the udevdb and can be queried from there with one of the
1584 o A few binaries are silently added to the repository, which can be used
1585 to replay kernel events from initramfs instead of using coldplug. udevd
1586 can be instructed now to queue-up events while the stored events from
1587 initramfs are filled into the udevd-queue. This code is still under
1588 development and there is no documentation now besides the code itself.
1589 The additional binaries get compiled, but are not installed by default.
1591 o There is also a temporary fix for a performance problem where too many
1592 events happen in parallel and every event needs to parse the rules.
1593 udev can now read precompiled rules stored on disk. This is likely to be
1594 replaced by a more elegant solution in a future udev version.
1598 With kernel version 2.6.12, the sysfs file "detached_state" was removed.
1599 Fix for libsysfs not to expect this file was added.
1603 All rules are applied now, but only the first matching rule with a NAME-key
1604 will be applied. All later rules with NAME-key are completely ignored. This
1605 way system supplied symlinks or permissions gets applied to user-defined
1609 Please check your rules setup, if you may need to add OPTIONS="last_rule"
1610 to some rules, to keep the old behavior.
1612 The rules are read on "remove"-events too. That makes is possible to match
1613 with keys that are available on remove (KERNEL, SUBSYSTEM, ID, ENV, ...) to
1614 instruct udev to ignore an event (OPTIONS="ignore_device").
1615 The new ACTION-key may be used to let a rule act only at a "remove"-event.
1617 The new RUN-key supports rule-based execution of programs after device-node
1618 handling. This is meant as a general replacement for the dev.d/-directories
1619 to give fine grained control over the execution of programs.
1621 The %s{}-sysfs format char replacement values are searched at any of the
1622 devices in the device chain now, not only at the class-device.
1624 We support log priority levels now. The value udev_log in udev.conf is used
1625 to determine what is printed to syslog. This makes it possible to
1626 run a version with compiled-in debug messages in a production environment
1627 which is sometimes needed to find a bug.
1628 It is still possible to supress the inclusion of _any_ syslog usage with
1629 USE_LOG=false to create the smallest possible binaries if needed.
1630 The configured udev_log value can be overridden with the environment variable
1635 Possible use of a system-wide klibc:
1636 make USE_KLIBC=true KLCC=/usr/bin/klcc all
1637 will link against an external klibc and our own version will be ignored.
1641 We support an unlimited count of symlinks now.
1643 If USE_STATIC=true is passed to a glibc build, we link statically and use
1644 a built-in userdb parser to resolve user and group names.
1646 The PLACE= key is gone. It can be replaced by an ID= for a long time, because
1647 we walk up the chain of physical devices to find a match.
1649 The KEY="<value>" format supports '=', '==', '!=,' , '+=' now. This makes it
1650 easy to skip certain attribute matches without composing rules with weird
1651 character class negations like:
1652 KERNEL="[!s][!c][!d]*"
1653 this can now be replaced with:
1655 The current simple '=' is still supported, and should work as it does today,
1656 but existing rules should be converted if possible, to be better readable.
1658 We have new ENV{}== key now, to match against a maximum of 5 environment
1661 udevstart is its own binary again, because we don't need co carry this araound
1662 with every forked event.