[systemd-devel] [HEADS-UP] If you are working on a multi-seat aware display manager

[Lennart Poettering]

Heya,

just a quick heads up if you are hacking on a multi-seat aware display
manager: with current git there is a new property CanGraphical on each
seat, and you probably should update your display manager to care for
this field, so that you properly handle seats which lack graphical
support. The main reason we added this field is to fix a race: when the
system comes up it might do so with a text console only, which is then
later on turned into a graphical one as the KMS driver is loaded and
video probed. We nowadays boot so fast that this might happen at a time
where your display manager has already been started, so you need to
watch CanGraphical so that you don't end up trying to start X11 on seat0
at a time where the KMS driver is not around yet.

There is also a new variable CanTTY for the reverse, which is handy in
some cases for USB graphics devices where the VT logic is not
available. This also paves the way for CONFIG_VT less kernels, like the
ones David Herrmann is working on.

I have updated the wiki to reflect this:

http://www.freedesktop.org/wiki/Software/systemd/writing-display-managers

Thanks,

Lennart

-- 
Lennart Poettering - Red Hat, Inc.