[systemd-devel] Antw: [EXT] Re: [systemd‑devel] device unit files

[Lennart Poettering]

On Do, 14.04.22 13:10, Ulrich Windl (Ulrich.Windl at rz.uni-regensburg.de) wrote:

> Apr 01 08:46:25 h16 kernel: sd 0:2:0:0: [sda] 467664896 512-byte logical
> blocks: (239 GB/223 GiB)
> ...
> Apr 01 08:46:33 h16 kernel: sd 3:0:7:2: [sdda] 524288 512-byte logical blocks:
> (268 MB/256 MiB)
> ...
> That's 8 seconds to discover the devices

That's not what udev triggering is about.

If hardware is slow to initialize it's slow to initialize, there's
nothing we can do about that from software.

triggering is merely the act of running udev rules for devices that
the kernel already knows about on boot, to implement what we call
"coldplug". it's about userspace catching up with kernel's
understanding of devices, that's all.

.device units show up once a device was announced by udev. that's
either due to coldplug (in case the device was aleady found by the
kernel before udev started) or hotplug (in case the device was found
later).

Lennart

--
Lennart Poettering, Berlin