On 12/23/11 5:14 AM, Eric Smith wrote:
> Now if I try to launch gsmartcontrol from the Gnome Shell, I get
> the prompt from userhelper for my password, but it fails to run.
> From the command line, the same thing happens, but at least it
> shows the error message "Gtk-WARNING **: cannot open display: :0".
I withdraw the question. After rebooting the system, gsmartcontrol and
gparted both work fine. I'm not sure what went wrong before.
You moved between networks, which caused your hostname to change .
This meant that the xauth cookie for your current session no longer
matched, because it embeds the hostname, because the spec says that's
what you do.
We set up X with two levels of authentication. The second is the
traditional xauth cookie mechanism, but the first matches against UID
% DISPLAY=:0 xhost
access control enabled, only authorized clients can connect
So this keeps normal users from being affected when the hostname
changes. But once you've switched UID you fall back to the xauth cookie
and things break.
I wrote a patch for this once:
And it got no conclusive testing or whatever, I forget. The patch
itself is in package git, although not enabled in the libXau build:
If someone wanted to test it, that'd rule.
 - This is debateably correct.
 - The real reason we do this is because it eliminates the security
issues if your ~ is on NFS, and because it keeps you from needing to
touch (ie, wake up) the disk in the common case.