There is, of course, one use for "settle"; I like to have a "monitor" running during boot that creates /var/log/udev - settle is as good a command as any to kill monitor when it's done. On Thu, Mar 31, 2011 at 11:35 AM, Kay Sievers <kay.sievers@xxxxxxxx> wrote: > Hey, > > the underlying problem described below, is in no way specific to > systemd, it applies to all modern systems and services, existing ones, > or ones not even developed. > > The udev systemd service files for udev do no longer pull-in the > barrier 'udevadm settle'. The udev coldplug run is executed fully > asynchronously in the background along with many other services, and > no other service will be blocked by default, waiting for udev to > populate /dev. > > That means: non-hotplug-aware services are likely to break. Services > which assume a static /dev, rely on scanning /dev and finding "all" > devices at a certain point in time, are required to explicitly pull-in > udev-settle.service to paper-over their inability to cope with a > dynamic system. It will block the broken service until udev's coldplug > run has finished and /dev is populated with all devices known at that > time. > > It's 2011 and services should cope with hotplug, devices coming and > going at any time, and a constantly changing and re-configuring > environment. No service which wants survive the next years of Linux > evolution should depend on the udev-settle.service barrier though, > please fix your stuff, or the reality might go on without you. :) > > There is libudev, which connects your service to meaningful event for > news devices, device changes, and allows you to enumerate all > currently existing devices. Subscribing to events before enumeration > is started will make sure not to miss anything, and to propagate later > changes into the service. > > All that even works from python, java, mono, javascript, ... programs, > so there is no excuse anymore to continue to do any of the > much-too-simple things we all did in the past. Just stop making > assumptions like: "booting has finished" or "all devices are there" -- > that never really was in the past, and it will never be true in the > future. > > Thanks, > 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 > -- 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
