Starting X with VGA on and LVDS off

Wolfgang Draxinger wdraxinger.maillist at
Sat Jan 7 01:42:51 PST 2012

On Sat, 07 Jan 2012 06:54:46 +0200
Maxim Levitsky <maximlevitsky at> wrote:

> > Here's a video for you, where I do exactly this:
> >
> I see what he means.
> The point is that when last X client exits, X undergoes internal
> reset. Then he probably runs xrand as such first and last client.
> When WM is running, it serves the purpose of an client that always
> runs, thus prevents this situation.

Yes, but the X server reset is not a restart, and doesn't "reset" the
output configuration. In the "old days" of XVidMode extension, or
multiple resolutions set, switched with CTRL+ALT+NUM_PLUS
CTRL+ALT+NUM_MINUS a server reset didn't switch the resolution back to
default either.

If I'm reading the spec correctly, then X server reset affects the
internal state of the server, that has an immediate influence on the
operation of the clients. The documentation says Atoms, Properties,
Input mappings.

Plus a program like xrandr can set XSetCloseDownMode to RetainTemporary
or RetainPersistent to prevent the X server from doing a reset should
it be the last client to disconnect – which in the case of xrandr would
make very much sense.

At least I can execute xrandr on all my machines as the only client,
reconfiguring output settings, without the X server switching to
default output after xrandr disconnecting. And unless I missed it, my
installed xrandr doesn't set XSetCloseDownMode. Last but not least, an
X server resetting output configuration after last client disconnect
would be very impractical.


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