Re: GNU Emacs now runs in foreground

From: Daniel Kahn Gillmor <dkg_at_fifthhorseman.net>
Date: Tue, 06 Dec 2016 18:12:36 -0500

On Tue 2016-12-06 07:15:49 -0500, Jonathan de Boyne Pollard wrote:
> and the Desktop Environment people are making away from per-session
> instances of the D-BUS daemon to per-user instances of the same. This
> causes fun with deciding what the daemon's $DISPLAY should be set to.

fwiw, dbus-user-session supports at most one graphical session
concurrently.

from "apt-cache show dbus-user-session:

Package: dbus-user-session
[…]
 Multiple graphical sessions per user are not currently supported in this
 mode; as a result, it is particularly suitable for gdm, which responds to
 requests to open a parallel graphical session by switching to the existing
 graphical session and unlocking it.
[…]

> A per-session Desktop Bus obviously has one $DISPLAY by and large.
> But a per-user Desktop Bus not only has to handle multiple logins from
> a single user, it has to handle that the per-user session management
> can be running when there's no X server at all.

in the dbus-user-session model, there can be 0 or 1 attached $DISPLAYs
-- this is different from "exactly 1 $DISPLAY" but it's hardly difficult
to decide what the $DISPLAY should be. it's either the empty string, or
it's the connected $DISPLAY.

> In practice, thus, the implementation of the user-wide client-server
> idea is half-hearted and flawed in this respect.

Yet surely there are some user-wide services that don't need DISPLAY at
all, and would be happy to run per-user?


     --dkg
Received on Tue Dec 06 2016 - 23:12:36 UTC