From: David Herrmann <dh.herrmann@gmail.com>
Date: Thu, 28 Nov 2013 14:10:24 +0000 (+0100)
Subject: logind: mute/restore VT on behalf of session controllers
X-Git-Tag: v209~1251
X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=commitdiff_plain;h=90a18413f8be577a649900eca977e060273f2b5b;hp=90a18413f8be577a649900eca977e060273f2b5b

logind: mute/restore VT on behalf of session controllers

If a session process calls TakeControl(), we now put the VT into
KD_GRAPHICS+K_OFF mode. This way, the new session controller can solely
rely on the logind-dbus API to manage the session.

Once the controller exits or calls ReleaseControl(), we restore the VT. We
also restore it, if we lost a controller during crash/restart (but only if
there really *was* a controller previously).

Note that we also must put the VT into VT_PROCESS mode. We want VT_AUTO
semantics, but VT_AUTO+KD_GRAPHICS actually disables *all* VT switches
(who came up with that great idea?). Hence, we set VT_PROCESS for logind
but acknowledge *all* requests immediately.

If a compositor wants custom VT setups, they can still get this by *first*
calling TakeControl() and afterwards setting up the VT. logind doesn't
touch the VT during controller runtime, only during setup/teardown. This
is actually what weston already does.
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