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 The expected value of '--libexecdir' has changed and must no longer contain
22 Kernel modules are now loaded directly by linking udev to 'libkmod'. The
23 'modprobe' tool is no longer executed by udev.
25 The 'blkid' tool is no longer executed from udev rules. Udev links
26 directly to libblkid now.
28 Firmware is loaded natively by udev now, the external 'firmware' binary
31 All built-in tools can be listed and tested with 'udevadm test-builtin'.
33 The 'udevadm control --reload-rules' option has been renamed to '--reload'.
34 It reloads the kernel module configuration.
36 The systemd socket files use PassCredentials=yes, which requires systemd
39 The udev build system only creates a .xz tarball now.
49 The udev daemon moved to /lib/udev/udevd. Non-systemd init systems
50 and non-dracut initramfs image generators need to change the init
51 scripts. Alternatively the udev build needs to move udevd back to
52 /sbin or create a symlink in /sbin, which is not done by default.
54 The path_id, usb_id, input_id tools are built-in commands now and
55 the stand-alone tools do not exist anymore. Static lists of file in
56 initramfs generators need to be updated. For testing, the commands
57 can still be executed standalone with 'udevadm test-builtin <cmd>'.
59 The fusectl filesystem is no longer mounted directly from udev.
60 Systemd systems will take care of mounting fusectl and configfs
61 now. Non-systemd systems need to ship their own rule if they
62 need these filesystems auto-mounted.
64 The long deprecated keys: SYSFS=, ID=, BUS= have been removed.
66 The support for 'udevadm trigger --type=failed, and the
67 RUN{fail_event_on_error} attribute was removed.
69 The udev control socket is now created in /run/udev/control
70 and no longer as an abstract namespace one.
72 The rules to create persistent network interface and cdrom link
73 rules automatically in /etc/udev/rules.d/ have been disabled by
74 default. Explicit configuration will be required for these use
75 cases, udev will no longer try to write any persistent system
76 configuration from a device hotplug path.
82 The udev-acl extra is no longer enabled by default now. To enable it,
83 --enable-udev_acl needs to be given at ./configure time. On systemd
84 systems, the udev-acl rules prevent it from running as the functionality
91 Udev now enables kernel media-presence polling if available. Part
92 of udisks optical drive tray-handling moved to cdrom_id: The tray
93 is locked as soon as a media is detected to enable the receiving
94 of media-eject-request events. Media-eject-request events will
97 Libudev enumerate is now able to enumerate a subtree of a given
100 The mobile-action-modeswitch modeswitch tool was deleted. The
101 functionality is provided by usb_modeswitch now.
107 The systemd service files require systemd version 28. The systemd
108 socket activation make it possible now to start 'udevd' and 'udevadm
109 trigger' in parallel.
113 Fix bug in control message handling, which can lead to a failing
114 udevadm control --exit. Thanks to Jürg Billeter for help tracking
121 We require at least Linux kernel 2.6.32 now. Some platforms might
122 require a later kernel that supports accept4() and similar, or
123 need to backport the trivial syscall wiring to the older kernels.
125 The hid2hci tool moved to the bluez package and was removed.
127 Many of the extras can be --enable/--disabled at ./configure
128 time. The --disable-extras option was removed. Some extras have
129 been disabled by default. The current options and their defaults
130 can be checked with './configure --help'.
136 Udev logs a warning now if /run is not writable at udevd
137 startup. It will still fall back to /dev/.udev, but this is
138 now considered a bug.
140 The running udev daemon can now cleanly shut down with:
141 udevadm control --exit
143 Udev in initramfs should clean the state of the udev database
144 with: udevadm info --cleanup-db which will remove all state left
145 behind from events/rules in initramfs. If initramfs uses
146 --cleanup-db and device-mapper/LVM, the rules in initramfs need
147 to add OPTIONS+="db_persist" for all dm devices. This will
148 prevent removal of the udev database for these devices.
150 Spawned programs by PROGRAM/IMPORT/RUN now have a hard timeout of
151 120 seconds per process. If that timeout is reached the spawned
152 process will be killed. The event timeout can be overwritten with
155 If systemd is used, udev gets now activated by netlink data.
156 Systemd will bind the netlink socket which will buffer all data.
157 If needed, such setup allows a seemless update of the udev daemon,
158 where no event can be lost during a udevd update/restart.
159 Packages need to make sure to: systemctl stop udev.socket udev.service
160 or 'mask' udev.service during the upgrade to prevent any unwanted
161 auto-spawning of udevd.
162 This version of udev conflicts with systemd version below 25. The
163 unchanged service files will not wirk correctly.
169 The udev runtime data moved from /dev/.udev/ to /run/udev/. The
170 /run mountpoint is supposed to be a tmpfs mounted during early boot,
171 available and writable to for all tools at any time during bootup,
172 it replaces /var/run/, which should become a symlink some day.
174 If /run does not exist, or is not writable, udev will fall back using
177 On systemd systems with initramfs and LVM used, packagers must
178 make sure, that the systemd and initramfs versions match. The initramfs
179 needs to create the /run mountpoint for udev to store the data, and
180 mount this tmpfs to /run in the rootfs, so the that the udev database
181 is preserved for the udev version started in the rootfs.
183 The command 'udevadm info --convert-db' is gone. The udev daemon
184 itself, at startup, converts any old database version if necessary.
186 The systemd services files have been reorganized. The udev control
187 socket is bound by systemd and passed to the started udev daemon.
188 The udev-settle.service is no longer active by default. Services which
189 can not handle hotplug setups properly need to actively pull it in, to
190 act like a barrier. Alternatively the settle service can be unconditionally
191 'systemctl'enabled, and act like a barrier for basic.target.
193 The fstab_import callout is no longer built or installed. Udev
194 should not be used to mount, does not watch changes to fstab, and
195 should not mirror fstab values in the udev database.
201 New and updated keymaps.
207 The udev database has changed, After installation of a new udev
208 version, 'udevadm info --convert-db' should be called, to let the new
209 udev/libudev version read the already stored data.
211 udevadm now supports quoting of property values, and prefixing of
213 $ udevadm info --export --export-prefix=MY_ --query=property -n sda
216 MY_DEVNAME='/dev/sda'
220 libudev now supports:
221 udev_device_get_is_initialized()
222 udev_enumerate_add_match_is_initialized()
223 to be able to skip devices the kernel has created , but udev has
226 libudev now supports:
227 udev_device_get_usec_since_initialized()
228 to retrieve the "age" of a udev device record.
230 GUdev supports a more generic GUdevEnumerator class, udev TAG
231 handling, device initialization and timestamp now.
233 The counterpart of /sys/dev/{char,block}/$major:$minor,
234 /dev/{char,block}/$major:$minor symlinks are now unconditionally
235 created, even when no rule files exist.
237 New and updated keymaps.
243 GUdev moved from /usr to /.
253 Persistent network naming rules are disabled inside of Qemu/KVM now.
255 New and updated keymaps.
257 Udev gets unconditionally enabled on systemd installations now. There
258 is no longer the need to to run 'systemctl enable udev.service'.
272 New and fixed keymaps.
274 Install systemd service files if applicable.
280 All distribution specific rules are removed from the udev source tree,
281 most of them are no longer needed. The Gentoo rules which allow to support
282 older kernel versions, which are not covered by the default rules anymore
283 has moved to rules/misc/30-kernel-compat.rules.
289 The option --debug-trace and the environemnt variable UDEVD_MAX_CHILDS=
290 was removed from udevd.
292 Udevd now checks the kernel commandline for the following variables:
293 udev.log-priority=<syslog priority>
294 udev.children-max=<maximum number of workers>
295 udev.exec-delay=<seconds to delay the execution of RUN=>
296 to help debuging coldplug setups where the loading of a kernel
297 module crashes the system.
299 The subdirectory in the source tree rules/packages has been renamed to
300 rules/arch, anc contains only architecture specific rules now.
310 Now the udev daemon itself, does on startup:
311 - copy the content of /lib/udev/devices to /dev
312 - create the standard symlinks like /dev/std{in,out,err},
313 /dev/core, /dev/fd, ...
314 - use static node information provided by kernel modules
315 and creates these nodes to allow module on-demand loading
316 - possibly apply permissions to all ststic nodes from udev
317 rules which are annotated to match a static node
319 The default mode for a device node is 0600 now to match the kernel
320 created devtmpfs defaults. If GROUP= is specified and no MODE= is
321 given the default will be 0660.
327 Udev now gradually starts to pass control over the primary device nodes
328 and their names to the kernel, and will in the end only manage the
329 permissions of the node, and possibly create additional symlinks.
330 As a first step NAME="" will be ignored, and NAME= setings with names
331 other than the kernel provided name will result in a logged warning.
332 Kernels that don't provide device names, or devtmpfs is not used, will
333 still work as they did before, but it is strongly recommended to use
334 only the same names for the primary device node as the recent kernel
335 provides for all devices.
339 Fix broken firmware loader search path.
345 "udevadm trigger" defaults to "change" events now instead of "add"
346 events. The "udev boot script" might need to add "--action=add" to
347 the trigger command if not already there, in case the initial coldplug
348 events are expected as "add" events.
350 The option "all_partitons" was removed from udev. This should not be
351 needed for usual hardware. Udev can not safely make assumptions
352 about non-existing partition major/minor numbers, and therefore no
353 longer provide this unreliable and unsafe option.
355 The option "ignore_remove" was removed from udev. With devtmpfs
356 udev passed control over device nodes to the kernel. This option
357 should not be needed, or can not work as advertised. Neither
358 udev nor the kernel will remove device nodes which are copied from
359 the /lib/udev/devices/ directory.
361 All "add|change" matches are replaced by "!remove" in the rules and
362 in the udev logic. All types of events will update possible symlinks
363 and permissions, only "remove" is handled special now.
365 The modem modeswitch extra was removed and the external usb_modeswitch
366 program should be used instead.
368 New and fixed keymaps.
378 Kernels with SYSFS_DEPRECATED=y are not supported since a while. Many users
379 depend on the current sysfs layout and the information not available in the
380 deprecated layout. All remaining support for the deprecated sysfs layout is
385 Fix for a possible endless loop in the new input_id program.
391 The option "ignore_device" does no longer exist. There is no way to
392 ignore an event, as libudev events can not be suppressed by rules.
393 It only prevented RUN keys from being executed, which results in an
394 inconsistent behavior in current setups.
396 BUS=, SYSFS{}=, ID= are long deprecated and should be SUBSYSTEM(S)=,
397 ATTR(S){}=, KERNEL(S)=. It will cause a warning once for every rule
400 The support for the deprecated IDE devices has been removed from the
401 default set of rules. Distros who still care about non-libata drivers
402 need to add the rules to the compat rules file.
404 The ID_CLASS property on input devices has been replaced by the more accurate
405 set of flags ID_INPUT_{KEYBOARD,KEY,MOUSE,TOUCHPAD,TABLET,JOYSTICK}. These are
406 determined by the new "input_id" prober now. Some devices, such as touchpads,
407 can have several classes. So if you previously had custom udev rules which e. g.
408 checked for ENV{ID_CLASS}=="kbd", you need to replace this with
409 ENV{ID_INPUT_KEYBOARD}=="?*".
415 To support DEVPATH strings larger than the maximum file name length, the
416 private udev database format has changed. If some software still reads the
417 private files in /dev/.udev/, which it shouldn't, now it's time to fix it.
418 Please do not port anything to the new format again, everything in /dev/.udev
419 is and always was private to udev, and may and will change any time without
422 Multiple devices claiming the same names in /dev are limited to symlinks
423 only now. Mixing identical symlink names and node names is not supported.
424 This reduces the amount of data in the database significantly.
426 NAME="%k" causes a warning now. It's is and always was completely superfluous.
427 It will break kernel supplied DEVNAMEs and therefore it needs to be removed
430 Most NAME= instructions got removed. Kernel 2.6.31 supplies the needed names
431 if they are not the default. To support older kernels, the NAME= rules need to
432 be added to the compat rules file.
434 Symlinks to udevadm with the old command names are no longer resolved to
435 the udevadm commands.
437 The udev-acl tool got adopted to changes in ConsoleKit. Version 0.4.1 is
440 The option "last_rule" does no longer exist. Its use breaks too many
441 things which expect to be run from independent later rules, and is an idication
442 that something needs to be fixed properly instead.
444 The gudev API is no longer marked as experimental,
445 G_UDEV_API_IS_SUBJECT_TO_CHANGE is no longer needed. The gudev introspection
446 is enabled by default now. Various projects already depend on introspection
447 information to bind dynamic languages to the gudev interfaces.
453 The udevadm trigger "--retry-failed" option, which is replaced since quite
454 a while by "--type=failed" is removed.
456 The failed tracking was not working at all for a few releases. The RUN
457 option "ignore_error" is replaced by a "fail_event_on_error" option, and the
458 default is not to track any failing RUN executions.
460 New keymaps, new modem, hid2hci updated.
464 Fix possible crash in udevd when worker processes are busy, rules are
465 changed at the same time, and workers get killed to reload the rules.
471 Properties set with ENV{.FOO}="bar" are marked private by starting the
472 name with a '.'. They will not be stored in the database, and not be
473 exported with the event.
475 Firmware files are looked up in:
476 /lib/firmware/updates/$(uname -r)
477 /lib/firmware/updates
478 /lib/firmware/$(uname -r)
482 ATA devices switched the property from ID_BUS=scsi to ID_BUS=ata.
483 ata_id, instead of scsi_id, is the default tool now for ATA devices.
489 The configure options have changed because another library needs to be
490 installed in a different location. Instead of exec_prefix and udev_prefix,
491 libdir, rootlibdir and libexecdir are used. The Details are explained in
494 Event processes now get re-used after they handled an event. This reduces
495 the number of forks and the pressure on the CPU significantly, because
496 cloned event processes no longer cause page faults in the main daemon.
497 After the events have settled, a few worker processes stay around for
498 future events, all others get cleaned up.
500 To be able to use signalfd(), udev depends on kernel version 2.6.25 now.
501 Also inotify support is mandatory now to run udev.
503 The format of the queue exported by the udev damon has changed. There is
504 no longer a /dev/.udev/queue/ directory. The current event queue can be
505 accessed with udevadm settle and libudedv.
507 Libudev does not have the unstable API header anymore. From now on,
508 incompatible changes will be handled by bumping the library major version.
510 To build udev from the git tree gtk-doc is needed now. The tarballs will
511 build without it and contain the pre-built documentation. An online copy
513 http://www.kernel.org/pub/linux/utils/kernel/hotplug/libudev/
515 The tools from the udev-extras repository have been merged into the main
516 udev repository. Some of the extras have larger external dependencies, and
517 they can be disabled with the configure switch --disable-extras.
523 The program vol_id and the library libvolume_id are removed from the
524 repository. Libvolume_id is merged with libblkid from the util-linux-ng
525 package. Persistent disk links for label and uuid depend on the
526 util-linux-ng version (2.15) of blkid now. Older versions of blkid
527 can not be used with udev.
529 Libudev allows to subscribe to udev events. To prevent unwanted messages
530 to be delivered, and waking up the subscribing process, a filter can be
531 installed, to drop messages inside a kernel socket filter. The filters
532 match on the <subsytem>:<devtype> properties of the device.
533 This is part of the ongoing effort to replace HAL, and switch current
534 users over to directly use libudev.
535 Libudev is still marked as experimental, and its interface might
536 eventually change if needed, but no major changes of the currently exported
537 interface are expected anymore, and a first stable release should happen
540 A too old kernel (2.6.21) or a kernel with CONFIG_SYSFS_DEPRECATED
541 is not supported since while and udevd will log an error message at
542 startup. It should still be able to boot-up, but advanced rules and system
543 services which depend on the information not available in the old sysfs
544 format will fail to work correctly.
546 DVB device naming is supplied by the kernel now. In case older kernels
547 need to be supported, the old shell script should be added to a compat
554 The processed udev events get send back to the netlink socket. Libudev
555 provides access to these events. This is work-in-progress, to replace
556 the DeviceKit daemon functionality directly with libudev. There are
557 upcoming kernel changes to allow non-root users to subcribe to these
564 "udevadm settle" now optionally accepts a range of events to wait for,
565 instead of waiting for "all" events.
571 The installed watch for block device metadata changes is now removed
572 during event hadling, because some (broken) tools may be called from udev
573 rules and (wrongly) open the device with write access. After the finished
574 event handling the watch is restored.
580 Device nodes can be watched for changes with inotify with OPTIONS="watch".
581 If closed after being opened for writing, a "change" uevent will occur.
582 /dev/disk/by-{label,uuid}/* symlinks will be automatically updated.
588 The udevadm test command has no longer a --force option, nodes and symlinks
589 are always updated with a test run now.
591 The udevd daemon can be started with --resolve-names=never to avoid all user
592 and group lookups (e.g. in cut-down systems) or --resolve-names=late to
593 lookup user and groups every time events are handled.
599 We are currently merging the Ubuntu rules in the udev default rules,
600 and get one step closer to provide a common Linux /dev setup, regarding
601 device names, symlinks, and default device permissions. On udev startup,
602 we now expect the following groups to be resolvable to their ids with
604 disk, cdrom, floppy, tape, audio, video, lp, tty, dialout, kmem.
605 LDAP setups need to make sure, that these groups are always resolvable at
606 bootup, with only the rootfs mounted, and without network access available.
608 Some systems may need to add some new, currently not used groups, or need
609 to add some users to new groups, but the cost of this change is minimal,
610 compared to the pain the current, rather random, differences between the
611 various distributions cause for upstream projects and third-party vendors.
613 In general, "normal" users who log into a machine should never be a member
614 of any such group, but the device-access should be managed by dynamic ACLs,
615 which get added and removed for the specific users on login/logout and
616 session activity/inactivity. These groups are only provided for custom setups,
617 and mainly system services, to allow proper privilege separation.
618 A video-streaming daemon uid would be a member of "audio" and "video", to get
619 access to the sound and video devices, but no "normal" user should ever belong
620 to the "audio" group, because he could listen to the built-in microphone with
621 any ssh-session established from the other side of the world.
623 /dev/serial/by-{id,path}/ now contains links for ttyUSB devices,
624 which do not depend on the kernel device name. As usual, unique
625 devices - only a single one per product connected, or a real
626 USB serial number in the device - are always found with the same
627 name in the by-id/ directory.
628 Completely identical devices may overwrite their names in by-id/
629 and can only be found reliably in the by-path/ directory. Devices
630 specified by by-path/ must not change their connection, like the
631 USB port number they are plugged in, to keep their name.
633 To support some advanced features, Linux 2.6.22 is the oldest supported
634 version now. The kernel config with enabled SYSFS_DEPRECATED is no longer
635 supported. Older kernels should still work, and devices nodes should be
636 reliably created, but some rules and libudev will not work correctly because
637 the old kernels do not provide the expected information or interfaces.
643 Fix for a possible segfault while swapping network interface names in udev
650 The group "video" is part of the default rules now.
654 Bugfix for kernels using SYSFS_DEPRECATED* option and finding parent
655 block devices in some cases. No common distro uses this option anymore,
656 and we do not get enough testing for this and recent udev versions. If
657 this option is not needed to run some old distro with a new kernel,
658 it should be disabled in the kernel config.
660 Bugfix for the $links substitution variable, which may crash if no links
661 are created. This should not happen in usual setups because we always
662 create /dev/{block,char}/ links.
664 The strings of the parsed rules, which are kept in memory, no longer
665 contain duplicate entries, or duplicate tails of strings. This, and the
666 new rules parsing/matching code reduces the total in-memory size of
667 a huge distro rule sets to 0.08 MB, compared to the 1.2MB of udev
670 The export of DEVTYPE=disk/partition got removed from the default
671 rules. This value is available from the kernel. The pnp shell script
672 modprobe hack is removed from the default rules. ACPI devices have _proper_
673 modalias support and take care of the same functionality.
674 Installations which support old kernels, but install current default
675 udev rules may want to add that to the compat rules file.
677 Libvolume_id now always probes for all known filesystems, and does not
678 stop at the first match. Some filesystems are marked as "exclusive probe",
679 and if any other filesytem type matches at the same time, libvolume_id
680 will, by default, not return any probing result. This is intended to prevent
681 mis-detection with conflicting left-over signatures found from earlier
682 file system formats. That way, we no longer depend on the probe-order
683 in case of multiple competing signatures. In some setups the kernel allows
684 to mount a volume with just the old filesystem signature still in place.
685 This may damage the new filesystem and cause data-loss, just by mounting
686 it. Because volume_id can not decide which one the correct signature is,
687 the wrong signatures need to be removed manually from the volume, or the
688 volume needs to be reformatted, to enable filesystem detection and possible
693 Fix segfault if compiled without optimization and dbg() does not get
694 compiled out and uses variables which are not available.
698 Bugfixes. (And maybe new bugs. :))
700 The rule matching engine got converted from a rule list to a token
701 array which reduced the in-memory rules representation of a full
702 featured distros with thousends of udev rules from 1.2MB to 0.12 MB.
703 Limits like 5 ENV and ATTR matches, and one single instance for most
704 other keys per rule are gone.
706 The NAME assignment is no longer special cased. If later rules assign
707 a NAME value again, the former value will be overwritten. As usual
708 for most other keys, the NAME value can be protected by doing a final
709 assignment with NAME:="<value>".
711 All udev code now uses libudev, which is also exported. The library
712 is still under development, marked as experimental, and its interface
713 may change as long as the DeviceKit integration is not finished.
715 Many thanks to Alan Jenkins for his continuous help, and finding and
716 optimizing some of the computing expensive parts.
722 Kernel devices and device nodes are connected now by reverse indizes in
723 /sys and /dev. A device number retrieved by a stat() or similar, the
724 kernel device directory can be found by looking up:
725 /sys/dev/{block,char}/<maj>:<min>
726 and the device node of the same device by looking up:
727 /dev/{block,char}/<maj>:<min>
731 Fix recently introduced bug, which caused a compilation without large
732 file support, where vol_id does not recognize raid signatures at the end
735 Firewire disks now create both, by-id/scsi-* and by-id/ieee-* links.
736 Seems some kernel versions prevent the creation of the ieee-* links,
737 so people used the scsi-* link which disappeared now.
739 More libudev work. Almost all udevadm functionality comes from libudev
742 udevadm trigger has a new option --type, which allows to trigger events
743 for "devices", for "subsystems", or "failed" devices. The old option
744 --retry-failed" still works, but is no longer mentioned in the man page.
750 The udevadm info --device-id-of-file= output has changed to use
751 the obvious format. Possible current users should use the --export
752 option which is not affected.
754 The old udev commands symlinks to udevadm are not installed, if
755 these symlinks are used, a warning is printed.
761 Optical drive's media is no longer probed for raid signatures,
762 reading the end of the device causes some devices to malfunction.
763 Also the offset of the last session found is used now to probe
766 The volume_id library got a major version number update to 1,
767 some deprecated functions are removed.
769 A shared library "libudev" gets installed now to provide access
770 to udev device information. DeviceKit, the successor of HAL, will
771 need this library to access the udev database and search sysfs for
773 The library is currently in an experimental state, also the API is
774 expected to change, as long as the DeviceKit integration is not
779 We use ./configure now. See INSTALL for details. Current
782 "/usr" - prefix for man pages, include files
784 "" - the root filesystem, prefix for libs and binaries
788 "lib" - directory name for libraries, not a path name
789 multilib 64bit systems may use "lib64" instead of "lib"
791 compile-in verbose debug messages
793 disable all logging and compile-out all log strings
795 link against SELInux libraries, to set the expected context
798 In the default rules, the group "disk" gets permissions 0660 instead
799 of 0640. One small step closer to unify distro rules. Some day, all
800 distros hopefully end up with the same set of rules.
802 No symlinks to udevadm are installed anymore, if they are still needed,
803 they should be provided by the package.
809 Default udev rules, which are not supposed to be edited by the user, should
810 be placed in /lib/udev/rules.d/ now, to make it clear that they are private to
811 the udev package and will be replaced with an update. Udev will pick up rule
813 /lib/udev/rules.d/ - default installed rules
814 /etc/udev/rules.d/ - user rules + on-the-fly generated rules
815 /dev/.udev/rules.d/ - temporary non-persistent rules created after bootup
816 It does not matter in which directory a rule file lives, all files are sorted
819 To help creating /dev/root, we have now:
820 $ udevadm info --export --export-prefix="ROOT_" --device-id-of-file=/
823 In case the current --device-id-of-file is already used, please switch to
824 the --export format version, it saves the output parsing and the old
825 format will be changed to use ':' as a separator, like the format in the
830 Fix cdrom_id to properly recognize blank media.
836 Tape drive id-data is queried from /dev/bsg/* instead of the tape
837 nodes. This avoids rewinding tapes on open().
843 The symlinks udevcontrol and udevtrigger are no longer installed by
846 The scsi_id program does not depend on sysfs anymore. It can speak
847 SGv4 now, so /dev/bsg/* device nodes can be used, to query SCSI device
848 data, which should solve some old problems with tape devices, where
849 we better do not open all tape device nodes to identify the device.
855 The cdrom_id program is replaced by an advanced version, which can
856 detect most common device types, and also properties of the inserted
857 media. This is part of moving some basic functionality from HAL into
858 udev (and the kernel).
864 The last WAIT_FOR_SYSFS rule is removed from the default rules.
866 The symlinks to udevadm for the debugging tools: udevmonitor and
867 udevtest are no longer created.
869 The symlinks to the udevadm man page for the old tool names are
872 Abstract namespace sockets paths in RUN+="socket:@<path>" rules,
873 should be prefixed with '@' to indicate that the path is not a
884 Udevstart is removed from the tree, it did not get installed for
885 a long time now, and is long replaced by trigger and settle.
891 All udev tools are merged into a single binary called udevadm.
892 The old names of the tools are built-in commands in udevadm now.
893 Symlinks to udevadm, with the names of the old tools, provide
894 the same functionality as the standalone tools. There is also
895 only a single udevadm.8 man page left for all tools.
897 Tools like mkinitramfs should be checked, if they need to include
898 udevadm in the list of files.
908 The etc/udev/rules.d/ directory now contains a default set of basic
909 udev rules. This initial version is the result of a rules file merge
910 of Fedora and openSUSE. For these both distros only a few specific
911 rules are left in their own file, named after the distro. Rules which
912 are optionally installed, because they are only valid for a specific
913 architecture, or rules for subsystems which are not always used are
914 in etc/udev/packages/.
920 Dynamic rules can be created in /dev/.udev/rules.d/ to trigger
921 actions by dynamically created rules.
923 SYMLINK=="<value>" matches agains the entries in the list of
924 currently defined symlinks. The links are not created in the
925 filesystem at that point in time, but the values can be matched.
927 RUN{ignore_error}+="<program>" will ignore any exit code from the
928 program and not record as a failed event.
934 Final merge of patches/features from the Ubuntu package.
940 Control characters in filesystem label strings are no longer silenty
941 removed, but hex-encoded, to be able to uniquely identify the device
942 by its symlink in /dev/disk/by-label/.
943 If libvolume_id is used by mount(8), LABEL= will work as expected,
944 if slashes or other characters are used in the label string.
946 To test the existence of a file, TEST=="<file>" and TEST!="<file>"
947 can be specified now. The TEST key accepts an optional mode mask
948 TEST{0100}=="<is executable file>".
950 Scsi_id now supports a mode without expecting scsi-specific sysfs
951 entries to allow the extraction of cciss-device persistent properties.
957 In the future, we may see uuid's which are just simple character
958 strings (see the DDF Raid Specification). For that reason vol_id now
959 exports ID_FS_UUID_SAFE, just like ID_FS_LABEL_SAFE. For things like
960 the creation of symlinks, the *_SAFE values ensure, that no control
961 or whitespace characters are used in the filename.
963 Possible users of libvolume_id, please use the volume_id_get_* functions.
964 The public struct will go away in a future release of the library.
970 Removal of useless extras/eventrecorder.sh.
980 The directory multiplexer for dev.d/ and hotplug.d are finally removed
981 from the udev package.
987 Symlinks can have priorities now, the priority is assigned to the device
988 and specified with OPTIONS="link_priority=100". Devices with higher
989 priorities overwrite the symlinks of devices with lower priorities.
990 If the device that currently owns the link, goes away, the symlink
991 will be removed, and recreated, pointing to the next device with the
992 highest actual priority. This should make /dev/disk/by-{label,uuid,id}
993 more reliable, if multiple devices contain the same metadata and overwrite
996 The dasd_id program is removed from the udev tree, and dasdinfo, with the
997 needed rules, are part of the s390-tools now.
999 Please add KERNEL=="[0-9]*:[0-9]*" to the scsi wait-for-sysfs rule,
1000 we may get the scsi sysfs mess fixed some day, and this will only catch
1001 the devices we are looking for.
1003 USB serial numbers for storage devices have the target:lun now appended,
1004 to make it possibble to distinguish broken multi-lun devices with all
1005 the same SCSI identifiers.
1007 Note: The extra "run_directory" which searches and executes stuff in
1008 /etc/hotplug.d/ and /etc/dev.d/ is long deprecated, and will be removed
1009 with the next release. Make sure, that you don't use it anymore, or
1010 provides your own implementation of that inefficient stuff.
1011 We are tired of reports about a "slow udev", because these directories
1012 contain stuff, that runs with _every_ event, instead of using rules,
1013 that run programs only for the matching events.
1023 DRIVER== will match only for devices that actually have a real
1024 driver. DRIVERS== must be used, if parent devices should be
1025 included in the match.
1027 Libvolume_id's "linux_raid" detection needed another fix.
1035 Add additional check to volume_id detection of via_raid, cause
1036 some company decided to put a matching pattern all over the empty
1037 storage area of their music players.
1041 Fix path_id for SAS devices.
1045 The udev daemon can be started with --debug-trace now, which will
1046 execute all events serialized to get a chance to catch a possible
1047 action that crashes the box.
1049 A warning is logged, if PHYSDEV* keys, the "device" link, or a parent
1050 device attribute like $attr{../file} is used, only WAIT_FOR_SYSFS rules
1051 are excluded from the warning. Referencing parent attributes directly
1052 may break when something in the kernel driver model changes. Udev will
1053 just find the attribute by walking up the parent chain.
1055 Udevtrigger now sorts the list of devices depending on the device
1056 dependency, so a "usb" device is triggered after the parent "pci"
1061 Revert persistent-storage ata-serial '_' '-' replacement.
1067 Udevtrigger can now filter the list of devices to be triggered. Matches
1068 for subsystems or sysfs attributes can be specified.
1070 The entries in /dev/.udev/queue and /dev/.udev/failed have changed to
1071 zero-sized files to avoid pointing to /sys and confuse broken tools which
1072 scan the /dev directory. To retry failed events, udevtrigger --retry-failed
1075 The rules and scripts to create udev rules for persistent network
1076 devices and optical drives are in the extras/rules_generator directory
1077 now. If you use something similar, please consider replacing your own
1078 version with this, to share the support effort. The rule_generator
1079 installs its own rules into /etc/udev/rules.d.
1081 The cdrom_id tool installs its own rule now in /etc/udev/rules.d, cause
1082 the rule_generator depends on cdrom_id to be called in an earlier rule.
1088 Renaming of some key names (the old names still work):
1089 BUS -> SUBSYSTEMS, ID -> KERNELS, SYSFS -> ATTRS, DRIVER -> DRIVERS.
1090 (The behavior of the key DRIVER will change soon in one of the next
1091 releases, to match only the event device, please switch to DRIVERS
1092 instead. If DRIVER is used, it will behave like DRIVERS, but an error
1094 With the new key names, we have a more consistent and simpler scheme.
1095 We can match the properties of the event device only, with: KERNEL,
1096 SUBSYSTEM, ATTR, DRIVER. Or include all the parent devices in the match,
1097 with: KERNELS, SUBSYSTEMS, ATTRS, DRIVERS. ID, BUS, SYSFS, DRIVER are no
1098 longer mentioned in the man page and should be switched in the rule
1101 ATTR{file}="value" can be used now, to write to a sysfs file of the
1102 event device. Instead of:
1103 ..., SYSFS{type}=="0|7|14", RUN+="/bin/sh -c 'echo 60 > /sys$$DEVPATH/timeout'"
1105 ..., ATTR{type}=="0|7|14", ATTR{timeout}="60"
1107 All the PHYSDEV* keys are deprecated and will be removed from a
1109 PHYDEVPATH - is the path of a parent device and should not be
1111 PHYSDEVBUS - is just a SUBSYSTEM value of a parent, and can be
1112 matched with SUBSYSTEMS==
1113 PHYSDEVDRIVER - for bus devices it is available as ENV{DRIVER}.
1114 Newer kernels will have DRIVER in the environment,
1115 for older kernels udev puts in. Class device will
1116 no longer carry this property of a parent and
1117 DRIVERS== can be used to match such a parent value.
1118 Note that ENV{DRIVER} is only available for a few bus devices, where
1119 the driver is already bound at device event time. On coldplug, the
1120 events for a lot devices are already bound to a driver, and they will have
1121 that value set. But on hotplug, at the time the kernel creates the device,
1122 it can't know what driver may claim the device after that, therefore
1123 in most cases it will be empty.
1125 Failed events should now be re-triggered with:
1126 udevtrigger --retry-failed.
1127 Please switch to this command, so we keep the details of the /dev/.udev/failed/
1128 files private to the udev tools. We may need to switch the current symlink
1129 target, cause some obviously broken tools try to scan all files in /dev
1130 including /dev/.udev/, find the links to /sys and end up stat()'ing sysfs files
1131 million times. This takes ages on slow boxes.
1133 The udevinfo attribute walk (-a) now works with giving a device node
1134 name (-n) instead of a devpath (-p). The query now always works, also when
1135 no database file was created by udev.
1137 The built-in /etc/passwd /etc/group parser is removed, we always depend on
1138 getpwnam() and getgrnam() now. One of the next releases will depend on
1139 fnmatch() and may use getopt_long().
1143 Bugfixes and small improvements.
1147 Fix path_id for recent kernels.
1153 Added support for swapping network interface names, by temporarily
1154 renaming the device and wait for the target name to become free.
1158 The built-in MODALIAS key and substitution is removed.
1162 The binary firmware helper is replaced by the usual simple
1163 shell script. Udevsend is removed from the tree.
1171 Some more keys require the correct use of '==' and '=' depending
1172 on the kind of operation beeing an assignment or a match. Rules
1173 with invalid operations are skipped and logged to syslog. Please
1174 test with udevtest if the parsing of your rules throws errors and
1175 fix possibly broken rules.
1179 Provide "udevsettle" to wait for all current udev events to finish.
1180 It also watches the current kernel netlink queue by comparing the
1181 even sequence number to make sure that there are no current pending
1182 events that have not already arrived in the daemon.
1186 Fix rule to skip persistent rules for removable IDE devices, which
1187 also skipped optical IDE drives.
1189 All *_id program are installed in /lib/udev/ by default now.
1191 No binary is stripped anymore as this should be done in the
1192 packaging process and not at build time.
1194 libvolume_id is provided as a shared library now and vol_id is
1195 linked against it. Also one of the next HAL versions will require
1196 this library, and the HAL build process will also require the
1197 header file to be installed. The copy of the same code in HAL will
1198 be removed to have only a single copy left on the system.
1202 Add persistent links for SCSI tapes. The rules file is renamed
1203 to 60-persistent-storage.rules.
1205 Create persistent path for usb devices. Can be used for all sorts
1206 of devices that can't be distinguished by other properties like
1207 multiple identical keyboards and mice connected to the same box.
1209 Provide "udevtrigger" program to request events on coldplug. The
1210 shell script is much too slow with thousends of devices.
1214 Fix persistent disk rules to exclude removable IDE drives.
1216 Warn if %e, $modalias or MODALIAS is used.
1220 Fix queue export, which wasn't correct for subsequent add/remove
1221 events for the same device.
1225 Fix cramfs detection on big endian.
1227 Make WAIT_FOR_SYSFS usable in "normal" rules and silent if the whole
1232 If BUS== and SYSFS{}== have been used in the same rule, the sysfs
1233 attributes were only checked at the parent device that matched the
1234 by BUS requested subsystem. Fix it to also look at the device we
1235 received the event for.
1237 Build variable CROSS has changed to CROSS_COMPILE to match the kernel
1242 Fix a bug where NAME="" would prevent RUN from beeing executed.
1244 RUN="/bin/program" does not longer automatically add the subsystem
1245 as the first parameter. This is from the days of /sbin/hotplug
1246 which is dead now and it's just confusing to need to add a space at
1247 the end of the program name to prevent this.
1248 If you use rules that need the subsystem as the first parameter,
1249 like the old "udev_run_hotlugd" and "udev_run_devd", add the subsystem
1250 to the key like RUN+="/bin/program $env{SUBSYSTEM}".
1254 The udev man page has moved to udev(7) as it does not describe a command
1255 anymore. The programs udev, udevstart and udevsend are no longer installed
1256 by default and must be copied manually, if they should be installed or
1257 included in a package.
1259 Fix a bug where "ignore_device" could run earlier collected RUN keys before
1260 the ignore rule was applied.
1262 More preparation for future sysfs changes. usb_id and scsi_id no longer
1263 depend on a magic order of devices in the /devices chain. Specific devices
1264 should be requested by their subsytem.
1266 This will always find the scsi parent device without depending on a specific
1268 dev = sysfs_device_get(devpath);
1269 dev_usb = sysfs_device_get_parent_with_subsystem(dev, "scsi");
1271 The "device" link in the current sysfs layout will be automatically
1272 _resolved_ as a parent and in the new sysfs layout it will just _be_ the
1273 parent in the devpath. If a device is requested by it's symlink, like all
1274 class devices in the new sysfs layout will look like, it gets automatically
1275 resolved and substituted with the real devpath and not the symlink path.
1278 A similar logic must be applied to _all_ sysfs users, including
1279 scripts, that search along parent devices in sysfs. The explicit use of
1280 the "device" link must be avoided. With the future sysfs layout all
1281 DEVPATH's will start with /devices/ and have a "subsystem" symlink poiting
1282 back to the "class" or the "bus". The layout of the parent devices in
1283 /devices is not necessarily expected to be stable across kernel releases and
1284 searching for parents by their subsystem should make sysfs users tolerant
1285 for changed parent chains.
1289 Prepare udev to work with the experimental kernel patch, that moves
1290 /sys/class devices to /sys/devices and /sys/block to /sys/class/block.
1292 Clarify BUS, ID, $id usage and fix $id behavior. This prepares for
1293 moving the class devices to /sys/devices.
1295 Thanks again to Marco for help finding a hopefully nice compromise
1296 to make %b simpler and working again.
1300 Complete removal of libsysfs, replaced by simple helper functions
1301 which are much simpler and a bit faster. The udev daemon operatesentirely
1302 on event parameters and does not use sysfs for simple rules anymore.
1303 Please report any new bugs/problems, that may be caused by this big
1304 change. They will be fixed immediately.
1306 The enumeration format character '%e' is deprecated and will be
1307 removed sometimes from a future udev version. It never worked correctly
1308 outside of udevstart, so we can't use it with the new parallel
1309 coldplug. A simple enumeration is as useless as the devfs naming
1310 scheme, just get rid of both if you still use it.
1312 MODALIAS and $modalias is not needed and will be removed from one of
1313 the next udev versions, replace it in all rules with ENV{MODALIAS} or
1314 the sysfs "modalias" value.
1316 Thanks a lot to Marco for all his help on finding and fixing bugs.
1320 Let scsi_id request libata drive serial numbers from page 0x80.
1322 Renamed etc/udev/persistent.rules to persistent-disk.rules and
1323 added /dev/disk/by-name/* for device mapper device names.
1325 Removed %e from the man page. It never worked reliably outside
1326 of udevstart and udevstart is no longer recommended to use.
1330 Symlinks are now exported to the event environment. Hopefully it's no
1331 longer needed to run udevinfo from an event process, like it was
1332 mentioned on the hotplug list:
1333 UDEV [1134776873.702967] add@/block/sdb
1336 DEVLINKS=/dev/disk/by-id/usb-IBM_Memory_Key_0218B301030027E8 /dev/disk/by-path/usb-0218B301030027E8:0:0:0
1340 Fix a problem if udevsend is used as the hotplug handler and tries to use
1341 syslog, which causes a "vc" event loop. 2.6.15 will make udevsend obsolete
1342 and this kind of problems will hopefully go away soon.
1346 All built-in logic to work around bad sysfs timing is removed with this
1347 version. The need to wait for sysfs files is almost fixed with a kernel
1348 version that doesn't work with this udev version anyway. Until we fix
1349 the timing of the "bus" link creation, the former integrated logic should
1350 be emulated by a rule placed before all other rules:
1351 ACTION=="add", DEVPATH=="/devices/*", ENV{PHYSDEVBUS}=="?*", WAIT_FOR_SYSFS="bus"
1353 The option "udev_db" does no longer exist. All udev state will be in
1354 /$udev_root/.udev/ now, there is no longer an option to set this
1356 If the init script or something else used this value, just depend on
1357 this hardcoded path. But remember _all_content_ of this directory is
1358 still private to udev and can change at any time.
1360 Default location for rule sripts and helper programs is now: /lib/udev/.
1361 Everything that is not useful on the commandline should go into this
1362 directory. Some of the helpers in the extras folder are installed there
1363 now. The rules need to be changed, to find the helpers there.
1365 Also /lib/udev/devices is recommended as a directory where packages or
1366 the user can place real device nodes, which get copied over to /dev at
1367 every boot. This should replace the various solutions with custom config
1370 Udevsend does no longer start the udev daemon. This must be done with
1371 the init script that prepares /dev on tmpfs and creates the initial nodes,
1372 before starting the daemon.
1376 Silent a too verbose error logging for the old hotplug.d/ dev.d/
1379 The copy of klibc is removed. A systemwide installed version of klibc
1380 should be used to build a klibc udev now.
1384 NAME="" will not create any nodes, but execute RUN keys. To completely
1385 ignore an event the OPTION "ignore_device" should be used.
1387 After removal of the reorder queue, events with a TIMEOUT can be executed
1388 without any queuing now.
1392 Fixed bug in udevd, if inotify is not available. We depend on netlink
1393 uevents now, kernels without that event source will not work with that
1394 version of udev anymore.
1398 The rule parsing happens now in the daemon once at startup, all udev
1399 event processes inherit the already parsed rules from the daemon.
1400 It is shipped with SUSE10.0 and reduces heavily the system load at
1401 startup. The option to save precompiled rules and let the udev process
1402 pick the them up is removed, as it's no longer needed.
1404 Kernel 2.6.15 will have symlinks at /class/input pointing to the real
1405 device. Libsysfs is changed to "translate" the requested link into the
1406 real device path, as it would happen with the hotplug event. Otherwise
1407 device removal and the udev database will not work.
1409 Using 'make STRIPCMD=' will leave the binaries unstripped for debugging
1412 A few improvements for vol_id, the filesytem probing code.
1416 Fix a stupid typo in extras/run_directory for "make install".
1418 scsi_id creates the temporary devnode now in /dev for usage with a
1419 non-writable /tmp directory.
1421 The uevent kernel socket buffer can carry app. 50.000 events now,
1422 let's see who can break this again. :)
1424 The upcoming kernel will have a new input driver core integration.
1425 Some class devices are now symlinks to the real device. libsysfs
1426 needs a fix for this to work correctly. Udevstart of older udev
1427 versions will _not_ create these devices!
1431 Fix a 'install' target in the Makefile, that prevents EXTRAS from
1436 A bunch of mostly trivial bugfixes. From now on no node name or
1437 symlink name can contain any character than plain whitelisted ascii
1438 characters or validated utf8 byte-streams. This is needed for the
1439 /dev/disk/by-label/* links, because we import untrusted data and
1440 export it to the filesystem.
1444 More bugfixes. If udevd was started from the kernel, we don't
1445 have stdin/stdout/stderr, which broke the forked tools in some
1450 Bugfix. udevstart event ordering was broken for a long time.
1451 The new run_program() uncovered it, because /dev/null was not
1452 available while we try to run external programs.
1453 Now udevstart should create it before we run anything.
1457 Minor bugfixes and some distro rules updates. If you don't have the
1458 persistent disk rules in /dev/disk/by-*/* on your distro, just
1459 grab it from here. :)
1463 We can use socket communication now to pass events from udev to
1465 RUN+="socket:/org/freedesktop/hal/udev_event"
1466 will pass the whole udev event to the HAL daemon without the need
1467 for a forked helper. (See ChangeLog for udevmonitor, as an example)
1471 Mostly bugfixes and see ChangeLog.
1473 The test for the existence of an environment value should be
1475 ENV{KEY}=="*" to ENV{KEY}=="?*"
1476 because "*" will not fail anymore, if the key does not exist or
1481 Bugfixes and a few tweaks described in the ChangeLog.
1485 Mostly a Bugfix release.
1487 Added WAIT_FOR_SYSFS="<attribute>" to be able to fight against the sysfs
1488 timing with custom rules.
1492 We changed the internal rule storage format. Our large rule files took
1493 2 MB of RAM, with the change we are down to 99kB.
1495 If the device-node has been created with default name and no symlink or
1496 options are to remenber, it is not longer stored in the udevdb. HAL will
1497 need to be updated to work correctly with that change.
1499 To overrride optimization flags, OPTFLAGS may be used now.
1507 Major changes happened with this release. The goal is to take over the
1508 complete kernel-event handling and provide a more efficient way to dispatch
1509 kernel events. Replacing most of the current shell script logic and the
1510 kernel forked helper with a netlink-daemon and a rule-based event handling.
1512 o udevd listens to netlink events now. The first valid netlink event
1513 will make udevd ignore any message from udevsend that contains a
1514 SEQNUM, to avoid duplicate events. The forked events can be disabled
1516 echo "" > /proc/sys/kernel/hotplug
1517 For full support, the broken input-subsytem needs to be fixed, not to
1518 bypass the driver core.
1520 o /etc/dev.d/ + /etc/hotplug.d/ directory multiplexing is completely
1521 removed from udev itself and must be emulated by calling small
1522 helper binaries provided in the extras folder:
1523 make EXTRAS=extras/run_directory/
1524 will build udev_run_devd and udev_run_hotplugd, which can be called
1525 from a rule if needed:
1526 RUN+="/sbin/udev_run_hotplugd"
1527 The recommended way to handle this is to convert all the calls from
1528 the directories to explicit udev rules and get completely rid of the
1529 multiplexing. (To catch a ttyUSB event, you now no longer need to
1530 fork and exit 300 tty script instances you are not interested in, it
1531 is just one rule that matches exactly the device.)
1533 o udev handles now _all_ events not just events for class and block
1534 devices, this way it is possible to control the complete event
1535 behavior with udev rules. Especially useful for rules like:
1536 ACTION="add", DEVPATH="/devices/*", MODALIAS=="?*", RUN+="/sbin/modprobe $modalias"
1538 o As used in the modalias rule, udev supports now textual
1539 substitution placeholder along with the usual format chars. This
1540 needs to be documented, for now it's only visible in udev_rules_parse.c.
1542 o The rule keys support now more operations. This is documented in the
1543 man page. It is possible to add values to list-keys like the SYMLINK
1544 and RUN list with KEY+="value" and to clear the list by assigning KEY="".
1545 Also "final"-assignments are supported by using KEY:="value", which will
1546 prevent changing the key by any later rule.
1548 o kernel 2.6.12 has the "detached_state" attribute removed from
1549 sysfs, which was used to recognize sysfs population. We switched that
1550 to wait for the "bus" link, which is only available in kernels after 2.6.11.
1551 Running this udev version on older kernels may cause a short delay for
1554 o To provide infrastructure for persistent device naming, the id programs:
1555 scsi_id, vol_id (former udev_volume_id), and ata_id (new) are able now
1556 to export the probed data in environment key format:
1557 pim:~ # /sbin/ata_id --export /dev/hda
1558 ID_MODEL=HTS726060M9AT00
1559 ID_SERIAL=MRH401M4G6UM9B
1560 ID_REVISION=MH4OA6BA
1562 The following rules:
1563 KERNEL="hd*[!0-9]", IMPORT="/sbin/ata_id --export $tempnode"
1564 KERNEL="hd*[!0-9]", ENV{ID_SERIAL}=="?*", SYMLINK+="disk/by-id/$env{ID_MODEL}_$env{ID_SERIAL}"
1567 kay@pim:~> tree /dev/disk
1570 | |-- HTS726060M9AT00_MRH401M4G6UM9B -> ../../hda
1571 | `-- IBM-Memory_Key -> ../../sda
1573 | |-- swap -> ../../hda1
1574 | |-- date -> ../../sda1
1575 | `-- home -> ../../hda3
1577 |-- 2E08712B0870F2E7 -> ../../hda3
1578 |-- 9352cfef-7687-47bc-a2a3-34cf136f72e1 -> ../../hda1
1579 |-- E845-7A89 -> ../../sda1
1580 `-- b2a61681-3812-4f13-a4ff-920d70604299 -> ../../hda2
1582 The IMPORT= operation will import these keys in the environment and make
1583 it available for later PROGRAM= and RUN= executed programs. The keys are
1584 also stored in the udevdb and can be queried from there with one of the
1587 o A few binaries are silently added to the repository, which can be used
1588 to replay kernel events from initramfs instead of using coldplug. udevd
1589 can be instructed now to queue-up events while the stored events from
1590 initramfs are filled into the udevd-queue. This code is still under
1591 development and there is no documentation now besides the code itself.
1592 The additional binaries get compiled, but are not installed by default.
1594 o There is also a temporary fix for a performance problem where too many
1595 events happen in parallel and every event needs to parse the rules.
1596 udev can now read precompiled rules stored on disk. This is likely to be
1597 replaced by a more elegant solution in a future udev version.
1601 With kernel version 2.6.12, the sysfs file "detached_state" was removed.
1602 Fix for libsysfs not to expect this file was added.
1606 All rules are applied now, but only the first matching rule with a NAME-key
1607 will be applied. All later rules with NAME-key are completely ignored. This
1608 way system supplied symlinks or permissions gets applied to user-defined
1612 Please check your rules setup, if you may need to add OPTIONS="last_rule"
1613 to some rules, to keep the old behavior.
1615 The rules are read on "remove"-events too. That makes is possible to match
1616 with keys that are available on remove (KERNEL, SUBSYSTEM, ID, ENV, ...) to
1617 instruct udev to ignore an event (OPTIONS="ignore_device").
1618 The new ACTION-key may be used to let a rule act only at a "remove"-event.
1620 The new RUN-key supports rule-based execution of programs after device-node
1621 handling. This is meant as a general replacement for the dev.d/-directories
1622 to give fine grained control over the execution of programs.
1624 The %s{}-sysfs format char replacement values are searched at any of the
1625 devices in the device chain now, not only at the class-device.
1627 We support log priority levels now. The value udev_log in udev.conf is used
1628 to determine what is printed to syslog. This makes it possible to
1629 run a version with compiled-in debug messages in a production environment
1630 which is sometimes needed to find a bug.
1631 It is still possible to supress the inclusion of _any_ syslog usage with
1632 USE_LOG=false to create the smallest possible binaries if needed.
1633 The configured udev_log value can be overridden with the environment variable
1638 Possible use of a system-wide klibc:
1639 make USE_KLIBC=true KLCC=/usr/bin/klcc all
1640 will link against an external klibc and our own version will be ignored.
1644 We support an unlimited count of symlinks now.
1646 If USE_STATIC=true is passed to a glibc build, we link statically and use
1647 a built-in userdb parser to resolve user and group names.
1649 The PLACE= key is gone. It can be replaced by an ID= for a long time, because
1650 we walk up the chain of physical devices to find a match.
1652 The KEY="<value>" format supports '=', '==', '!=,' , '+=' now. This makes it
1653 easy to skip certain attribute matches without composing rules with weird
1654 character class negations like:
1655 KERNEL="[!s][!c][!d]*"
1656 this can now be replaced with:
1658 The current simple '=' is still supported, and should work as it does today,
1659 but existing rules should be converted if possible, to be better readable.
1661 We have new ENV{}== key now, to match against a maximum of 5 environment
1664 udevstart is its own binary again, because we don't need co carry this araound
1665 with every forked event.