[systemd-devel] Tuning A/V at Boot

[Lennart Poettering]

On Sat, 08.06.13 22:00, Kok, Auke-jan H (auke-jan.h.kok at intel.com) wrote:

> 
> On Sat, Jun 8, 2013 at 5:43 PM,  <systemdkiosk at yopmail.com> wrote:
> > Where in boot sequence tune A/V latency? Is sound.target relevant?
> 
> anything device specific should be triggered from a udev rule, so that
> you're not running this service while the device isn't actually
> available yet to userspace...
> 
> systemd already installs a 99-systemd.rules file that has:
> 
> SUBSYSTEM=="sound", KERNEL=="card*", TAG+="systemd",
> ENV{SYSTEMD_WANTS}+="sound.target"
> 
> So linking your service file into sound.target.wants should work.
> (but, I haven't tested this particular case or taget myself).

sound.target is pulled in as soon as the first sound card is found, and
which one that is is entirely arbitrary. It's hence useless for setting
device specific properties. For that one should write an udev rule that
triggers on that specific device and issues its request from within the
rule.

Lennart

-- 
Lennart Poettering - Red Hat, Inc.