3 Mostly a Bugfix release.
5 Added WAIT_FOR_SYSFS="<attribute>" to be able to fight against the sysfs
6 timing with custom rules.
10 We changed the internal rule storage format. Our large rule files took
11 2 MB of RAM, with the change we are down to 99kB.
13 If the device-node has been created with default name and no symlink or
14 options are to remenber, it is not longer stored in the udevdb. HAL will
15 need to be updated to work correctly with that change.
17 To overrride optimization flags, OPTFLAGS may be used now.
25 Major changes happened with this release. The goal is to take over the
26 complete kernel-event handling and provide a more efficient way to dispatch
27 kernel events. Replacing most of the current shell script logic and the
28 kernel forked helper with a netlink-daemon and a rule-based event handling.
30 o udevd listens to netlink events now. The first valid netlink event
31 will make udevd ignore any message from udevsend that contains a
32 SEQNUM, to avoid duplicate events. The forked events can be disabled
34 echo "" > /proc/sys/kernel/hotplug
35 For full support, the broken input-subsytem needs to be fixed, not to
36 bypass the driver core.
38 o /etc/dev.d/ + /etc/hotplug.d/ directory multiplexing is completely
39 removed from udev itself and must be emulated by calling small
40 helper binaries provided in the extras folder:
41 make EXTRAS=extras/run_directory/
42 will build udev_run_devd and udev_run_hotplugd, which can be called
43 from a rule if needed:
44 RUN+="/sbin/udev_run_hotplugd"
45 The recommended way to handle this is to convert all the calls from
46 the directories to explicit udev rules and get completely rid of the
47 multiplexing. (To catch a ttyUSB event, you now no longer need to
48 fork and exit 300 tty script instances you are not interested in, it
49 is just one rule that matches exactly the device.)
51 o udev handles now _all_ events not just events for class and block
52 devices, this way it is possible to control the complete event
53 behavior with udev rules. Especially useful for rules like:
54 ACTION="add", DEVPATH="/devices/*", MODALIAS=="?*", RUN+="/sbin/modprobe $modalias"
56 o As used in the modalias rule, udev supports now textual
57 substitution placeholder along with the usual format chars. This
58 needs to be documented, for now it's only visible in udev_rules_parse.c.
60 o The rule keys support now more operations. This is documented in the
61 man page. It is possible to add values to list-keys like the SYMLINK
62 and RUN list with KEY+="value" and to clear the list by assigning KEY="".
63 Also "final"-assignments are supported by using KEY:="value", which will
64 prevent changing the key by any later rule.
66 o kernel 2.6.12 has the "detached_state" attribute removed from
67 sysfs, which was used to recognize sysfs population. We switched that
68 to wait for the "bus" link, which is only available in kernels after 2.6.11.
69 Running this udev version on older kernels may cause a short delay for
72 o To provide infrastructure for persistent device naming, the id programs:
73 scsi_id, vol_id (former udev_volume_id), and ata_id (new) are able now
74 to export the probed data in environment key format:
75 pim:~ # /sbin/ata_id --export /dev/hda
76 ID_MODEL=HTS726060M9AT00
77 ID_SERIAL=MRH401M4G6UM9B
81 KERNEL="hd*[!0-9]", IMPORT="/sbin/ata_id --export $tempnode"
82 KERNEL="hd*[!0-9]", ENV{ID_SERIAL}=="?*", SYMLINK+="disk/by-id/$env{ID_MODEL}_$env{ID_SERIAL}"
85 kay@pim:~> tree /dev/disk
88 | |-- HTS726060M9AT00_MRH401M4G6UM9B -> ../../hda
89 | `-- IBM-Memory_Key -> ../../sda
91 | |-- swap -> ../../hda1
92 | |-- date -> ../../sda1
93 | `-- home -> ../../hda3
95 |-- 2E08712B0870F2E7 -> ../../hda3
96 |-- 9352cfef-7687-47bc-a2a3-34cf136f72e1 -> ../../hda1
97 |-- E845-7A89 -> ../../sda1
98 `-- b2a61681-3812-4f13-a4ff-920d70604299 -> ../../hda2
100 The IMPORT= operation will import these keys in the environment and make
101 it available for later PROGRAM= and RUN= executed programs. The keys are
102 also stored in the udevdb and can be queried from there with one of the
105 o A few binaries are silently added to the repository, which can be used
106 to replay kernel events from initramfs instead of using coldplug. udevd
107 can be instructed now to queue-up events while the stored events from
108 initramfs are filled into the udevd-queue. This code is still under
109 development and there is no documentation now besides the code itself.
110 The additional binaries get compiled, but are not installed by default.
112 o There is also a temporary fix for a performance problem where too many
113 events happen in parallel and every event needs to parse the rules.
114 udev can now read precompiled rules stored on disk. This is likely to be
115 replaced by a more elegant solution in a future udev version.
119 With kernel version 2.6.12, the sysfs file "detached_state" was removed.
120 Fix for libsysfs not to expect this file was added.
124 All rules are applied now, but only the first matching rule with a NAME-key
125 will be applied. All later rules with NAME-key are completely ignored. This
126 way system supplied symlinks or permissions gets applied to user-defined
130 Please check your rules setup, if you may need to add OPTIONS="last_rule"
131 to some rules, to keep the old behavior.
133 The rules are read on "remove"-events too. That makes is possible to match
134 with keys that are available on remove (KERNEL, SUBSYSTEM, ID, ENV, ...) to
135 instruct udev to ignore an event (OPTIONS="ignore_device").
136 The new ACTION-key may be used to let a rule act only at a "remove"-event.
138 The new RUN-key supports rule-based execution of programs after device-node
139 handling. This is meant as a general replacement for the dev.d/-directories
140 to give fine grained control over the execution of programs.
142 The %s{}-sysfs format char replacement values are searched at any of the
143 devices in the device chain now, not only at the class-device.
145 We support log priority levels now. The value udev_log in udev.conf is used
146 to determine what is printed to syslog. This makes it possible to
147 run a version with compiled-in debug messages in a production environment
148 which is sometimes needed to find a bug.
149 It is still possible to supress the inclusion of _any_ syslog usage with
150 USE_LOG=false to create the smallest possible binaries if needed.
151 The configured udev_log value can be overridden with the environment variable
156 Possible use of a system-wide klibc:
157 make USE_KLIBC=true KLCC=/usr/bin/klcc all
158 will link against an external klibc and our own version will be ignored.
162 We support an unlimited count of symlinks now.
164 If USE_STATIC=true is passed to a glibc build, we link statically and use
165 a built-in userdb parser to resolve user and group names.
167 The PLACE= key is gone. It can be replaced by an ID= for a long time, cause
168 we walk up the chain of physical devices to find a match.
170 The KEY="<value>" format supports '=', '==', '!=,' , '+=' now. This makes it
171 easy to skip certain attribute matches without composing rules with weird
172 character class negations like:
173 KERNEL="[!s][!c][!d]*"
174 this can now be replaced with:
176 The current simple '=' is still supported, and should work as it does today,
177 but existing rules should be converted if possible, to be better readable.
179 We have new ENV{}== key now, to match against a maximum of 5 environment
182 udevstart is its own binary again, cause we don't need co carry this araound
183 with every forked event.