"Color" tool in GNOME System Settings only recognizes my webcam as color-manageable device

[Till Kamppeter]

When I open the GNOME System Settings and click on "Color", I am supposed to get the list of color-manageable (via colord) devices. As the only device I get my webcam there, not the screen, no printers, ... Seems to be a problem of colord not recognizing the devices or of GNOME System Settings not polling the info correctly from colord.

[Till Kamppeter (till-kamppeter)]

I am on a Lenovo Thinkpad T400 laptop, with Intel graphics.

[Chris Halse Rogers (raof)]

 affects ubuntu/colord
 status confirmed

I also see this, although I suspect there might be more than one bug
here.
*) As far as I can tell, colord doesn't actually try to enumerate
printers, and wants cups to use the org.freedesktop.ColorManager DBus
interface, so the lack of
*) Display profiles require integration with the session; as far as I
can tell this is done through gnome-settings-manager and
gnome-color-manager
*) There seems to be a problem with startup, where cups starts colord
but to enumerate my hpaio scanner colord appears to need to start after
cups.

So there might be three separate bugs here. I'll hunt things down.

[Till Kamppeter (till-kamppeter)]

Perhaps bug 833151 has influence on this, too.

[Till Kamppeter (till-kamppeter)]

I have checked CUPS and colord support is in since 1.5.0-2. It is introduced by debian/patches/colord-support.patch. The patch is actually applied as one can grep "org.freedesktop.ColorManager" in /usr/sbin/cupsd and it tells that the file matches. So one would need some D-Bus debugging to check whether colord is correctly polling the printer info from CUPS.

[Chris Halse Rogers (raof)]

Ah. After watching the DBus traffic it seems that this is partially due to the run-as-system-user patches. colord uses PolicyKit to check the user's authorisation, and PolicyKit doesn't allow an unpriviledged user to check whether a non-self user has priviledges. The error message generated is:

GDBus.Error:org.freedesktop.PolicyKit1.Error.NotAuthorized: Only trusted callers (e.g. uid 0) can use CheckAuthorization() for subjects belonging to other identities'

This means that applications that try to register devices with colord will fail, which is why the display and cups integration isn't working.

[Launchpad Janitor (janitor)]

This bug was fixed in the package colord - 0.1.11-1ubuntu2

---------------
colord (0.1.11-1ubuntu2) oneiric; urgency=low

  * debian/patches/06_use_dbus_security_for_permissions.diff:
    - Patch to allow root and at_console access to access the colord service.
      This matches the default PolicyKit rules.
  * debian/patches/07_fix_disable_polkit_build.diff:
    - Fix the build when passing --disable-polkit
  * debian/rules:
  * debian/control:
    - Disable PolicyKit support, in favour of the dbus security introduced
      above. PolicyKit is not usable as access control to a non-root service.
      (LP: #837851)
 -- Christopher James Halse Rogers <email address hidden> Fri, 02 Sep 2011 17:09:42 +1000

[Chris Halse Rogers (raof)]

Marking the gnome-control-centre task as invalid. This was purely a colord problem.