[CentOS] Problems with getty and X on runlevel switch [Was: Re: The future of centos]

Wed Apr 8 19:24:06 UTC 2015
Liam O'Toole <liam.p.otoole at gmail.com>

On 2015-04-08, Liam O'Toole
<liam.p.otoole at gmail.com> wrote:
> On 2015-04-08, Leon Fauster
><leonfauster at googlemail.com> wrote:
>> Am 08.04.2015 um 16:22 schrieb Liam O'Toole
>> <liam.p.otoole at gmail.com>:
>>> On 2015-04-08, David Both <dboth at millennium-technology.com> wrote:
>>>> The easy way to restart gdm is when you are on the login screen
>>>> itself or the desktop simply press Ctrl-Alt-Backspace. This works
>>>> for Upstart in CentOS 6.x but will not work for CentOS 7.x which
>>>> uses Systemd. The service command does not work for gdm. However,
>>>> logging out of the desktop will restart gdm. It works for the
>>>> graphical login exactly like the gettys in a TTY environment.
>>> 
>>> Thanks for the suggestion.
>>> 
>>> Logging out and keying ctrl-alt-backspace both restart X, certainly,
>>> but I'm not so sure about gdm. I'm not at a CentOS 6 machine right
>>> now so I can't confirm one way or the other.
>>
>>
>> gdm is a "sub-process" of X ...
>>
>> -- LF
>
> Not according to the output of pstree. See the following snippet:
>
>      ├─gdm-binary─┬─gdm-simple-slav─┬─Xorg │            │
>      ├─gdm-session-wor─┬─gnome-session─┬─bluetoo+ │            │
>      │                 │               ├─compiz─+ │            │
>      │                 │               │        + │            │
>      │                 │               ├─gdu-not+ │            │
>      │                 │               ├─gnome-p+ │            │
>      │                 │               ├─gpk-upd+ │            │
>      │                 │               ├─nautilu+ │            │
>      │                 │               ├─polkit-+ │            │
>      │                 │               ├─python │            │
>      │                 │               ├─restore+ │            │
>      │                 │               └─{gnome-+ │            │
>      │                 └─{gdm-session-wo} │            │
>      └─{gdm-simple-sla} │            └─{gdm-binary}
>
> Xorg is in fact a sub-sub-process of gdm-binary.
>
> While logged into a GNOME session, I ran the pgrep command as follows:
>
> $ pgrep -fl gdm 1583 /usr/sbin/gdm-binary -nodaemon 1619
> /usr/libexec/gdm-simple-slave --display-id
> /org/gnome/DisplayManager/Display1 1622 /usr/bin/Xorg :0 -br -verbose
> -audit 4 -auth /var/run/gdm/auth-for-gdm-EcVz3c/database -nolisten tcp
> vt1 1801 pam: gdm-password
>
> I restarted X using ctrl-alt-backspace, logged back in and ran the
> command again:
>
> $ pgrep -fl gdm 1583 /usr/sbin/gdm-binary -nodaemon 1619
> /usr/libexec/gdm-simple-slave --display-id
> /org/gnome/DisplayManager/Display1 1622 /usr/bin/Xorg :0 -br -verbose
> -audit 4 -auth /var/run/gdm/auth-for-gdm-EcVz3c/database -nolisten tcp
> vt1 1801 pam: gdm-password
>
> X has indeed restarted, but the gdm-related processes have not.
>

As a follow-up, running the command 'initctl restart prefdm' as
suggested by Johnathan did the trick:

$ pgrep -fl gdm
5728 /usr/sbin/gdm-binary -nodaemon
5744 /usr/libexec/gdm-simple-slave --display-id
/org/gnome/DisplayManager/Display1
5747 /usr/bin/Xorg :0 -br -verbose -audit 4 -auth
/var/run/gdm/auth-for-gdm-QmU6b6/database -nolisten tcp vt1
5804 pam: gdm-password

-- 

Liam