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Diffstat (limited to 'RELEASE-NOTES')
| -rw-r--r-- | RELEASE-NOTES | 99 |
1 files changed, 99 insertions, 0 deletions
diff --git a/RELEASE-NOTES b/RELEASE-NOTES index 9b7fa31330..46787704ce 100644 --- a/RELEASE-NOTES +++ b/RELEASE-NOTES @@ -1,3 +1,102 @@ +udev 059 +======== +Major changes happened with this release. The goal is to take over the +complete kernel-event handling and provide a more efficient way to dispatch +kernel events. Replacing most of the current shell script logic and the +kernel forked helper with a netlink-daemon and a rule-based event handling. + +o udevd listens to netlink events now. The first valid netlink event + will make udevd ignore any message from udevsend that contains a + SEQNUM, to avoid duplicate events. The forked events can be disabled + with: + echo "" > /proc/sys/kernel/hotplug + For full support, the broken input-subsytem needs to be fixed, not to + bypass the driver core. + +o /etc/dev.d/ + /etc/hotplug.d/ directory multiplexing is completely + removed from udev itself and must be emulated by calling small + helper binaries provided in the extras folder: + make EXTRAS=extras/run_directory/ + will build udev_run_devd and udev_run_hotplugd, which can be called + from a rule if needed: + RUN+="/sbin/udev_run_hotplugd" + The recommended way to handle this is to convert all the calls from + the directories to explicit udev rules and get completely rid of the + multiplexing. (To catch a ttyUSB event, you now no longer need to + fork and exit 300 tty script instances you are not interested in, it + is just one rule that matches exactly the device.) + +o udev handles now _all_ events not just events for class and block + devices, this way it is possible to control the complete event + behavior with udev rules. Especially useful for rules like: + ACTION="add", DEVPATH="/devices/*", MODALIAS=="?*", RUN+="/sbin/modprobe $modalias" + +o As used in the modalias rule, udev supports now textual + substitution placeholder along with the usual format chars. This + needs to be documented, for now it's only visible in udev_rules_parse.c. + +o The rule keys support now more operations. This is documented in the + man page. It is possible to add values to list-keys like the SYMLINK + and RUN list with KEY+="value" and to clear the list by assigning KEY="". + Also "final"-assignments are supported by using KEY:="value", which will + prevent changing the key by any later rule. + +o kernel 2.6.12 has the "detached_state" attribute removed from + sysfs, which was used to recognize sysfs population. We switched that + to wait for the "bus" link, which is only available in kernels after 2.6.11. + Running this udev version on older kernels may cause a short delay for + some events. + +o To provide infrastructure for persistent device naming, the id programs: + scsi_id, vol_id (former udev_volume_id), and ata_id (new) are able now + to export the probed data in environment key format: + pim:~ # /sbin/ata_id --export /dev/hda + ID_MODEL=HTS726060M9AT00 + ID_SERIAL=MRH401M4G6UM9B + ID_REVISION=MH4OA6BA + + The following rules: + KERNEL="hd*[!0-9]", IMPORT="/sbin/ata_id --export $tempnode" + KERNEL="hd*[!0-9]", ENV{ID_SERIAL}=="?*", SYMLINK+="disk/by-id/$env{ID_MODEL}_$env{ID_SERIAL}" + + Will create: + kay@pim:~> tree /dev/disk + /dev/disk + |-- by-id + | |-- HTS726060M9AT00_MRH401M4G6UM9B -> ../../hda + | `-- IBM-Memory_Key -> ../../sda + |-- by-label + | |-- swap -> ../../hda1 + | |-- date -> ../../sda1 + | `-- home -> ../../hda3 + `-- by-uuid + |-- 2E08712B0870F2E7 -> ../../hda3 + |-- 9352cfef-7687-47bc-a2a3-34cf136f72e1 -> ../../hda1 + |-- E845-7A89 -> ../../sda1 + `-- b2a61681-3812-4f13-a4ff-920d70604299 -> ../../hda2 + + The IMPORT= operation will import these keys in the environment and make + it available for later PROGRAM= and RUN= executed programs. The keys are + also stored in the udevdb and can be queried from there with one of the + next udev versions. + +o A few binaries are silently added to the repository, which can be used + to replay kernel events from initramfs instead of using coldplug. udevd + can be instructed now to queue-up events while the stored events from + initramfs are filled into the udevd-queue. This code is still under + development and there is no documentation now besides the code itself. + The additional binaries get compiled, but are not installed by default. + +o There is also a temporary fix for a performance problem where too many + events happen in parallel and every event needs to parse the rules. + udev can now read precompiled rules stored on disk. This is likely to be + replaced by a more elegant solution in a future udev version. + +udev 058 +======== +With kernel version 2.6.12, the sysfs file "detached_state" was removed. +Fix for libsysfs not to expect this file was added. + udev 057 ======== All rules are applied now, but only the first matching rule with a NAME-key |