On Mon, Sep 1, 2008 at 16:44, Francesco RUNDO <francesco.rundo@xxxxxx> wrote: > My name is Francesco Rundo and I work porting Linux (kernel, device drivers, > etc..) for embedded system. > > I've a question about udev, in particular way, I need to get some info about > udevstart and udevtrigger. > > In order to improve the boot speed, I've removed in my udev init scripts the > tool udevstart. Basically, in my udev init scripts (which start firstly in > the user space boot sequence) there are in order: > 1) some operation on /dev with manually creation of some devices; > 2) udevstart call; > 3) starting of udevd; > 4) udevtrigger call; > 5) udevsettle call; > After that, the common services will be initialized: ssh, D-bus, HAL, Lirc, > etc...; > > I've noted that this sequence is used in different Linux distribution for > embedded system. > > As far as I know, the tool "udevstart" has the target to populate initial > device directoty (/dev). It walks trough the sysfs device tree and calls > udev (daemon) to create the nodes for every valid device found. It is used > to fill the initial empty device directory with nodes for all devices > currently available. Is it right ? > > Now, I know that "udevtrigger" replies the uevents generated by system > coldplug of the devices (passing the info to the udev daemon) while > udevsettle waits watching the udev event queue and exits if all current > events are handled. Is it right ? > > By taking into account what above mentioned, I've removed from udev starting > script the tool "udevstart" which needs a lot of time to populate the device > (In my kernel config, I've a lot of device included in the kernel ) and I've > managed udev only with udevtrigger and udevsettle. In this way, the device > creation under /dev will be made by udevtrigger. I've saved 3/4 sec of boot > time!! > > Finally, I've to say that in some web site I've noted that some Linux > distribution were using this approach. Also the initNG project suggests to > remove udevstart using only udevtrigger & udevsettle. Please, see > http://www.initng.org/wiki/udevstart for more detail. > > Now the question is: > Is it right to remove udevstart using only udevtrigger ? > Are there some funcionality-restrictions in the udev if I don't use > udevstart ? > Is it true that starting from udev-117 udevstart will not be delivered ? > In my distribution, we are aligned to udev-116 Udevstart is obsolete and does not exist anymore. It was replaced, and is not installed since udev 082: http://git.kernel.org/?p=linux/hotplug/udev.git;a=commit;h=c233b59baaabe55a8f99dc37c4ee9011b85f8917 Kay -- To unsubscribe from this list: send the line "unsubscribe linux-hotplug" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
