[systemd-devel] Reliably waiting for udevd to finish processing triggered events

Daniel Drake drake at endlessm.com
Mon Mar 9 05:49:47 PDT 2015


On Sun, Mar 8, 2015 at 3:50 PM, Lennart Poettering
<lennart at poettering.net> wrote:
> On Fri, 06.03.15 14:22, Daniel Drake (drake at endlessm.com) wrote:
> To my knowledge newer versions don't do this anymore and actively
> watch drm devices coming.

I'm describing the behaviour of the newer version here. The issue is
current. It does watch drm devices but if it gets indication that all
udev events have been processed and still there is no usable drm
device, it will give up on drm and launch into text mode.

> No, applications should not watch the queue. And the file is internal
> to udev anyway. If you watch it, you get to keep the pieces.

The plymouth behaviour I described is achieved by using the public
libudev API, udev_queue_get_queue_is_empty() and (the exact equivalent
of) udev_queue_get_fd().


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