RandR questions

Pedro DeKeratry pdekeratry at gmail.com
Tue Nov 2 00:01:34 PDT 2010

First let me describe the behavior that prompted my questions. This is
on a laptop running Ubuntu Desktop 10.10 and the xorg.conf is
configured to run a mutli-display using the external HDMI and external
VGA ports, thus the laptop screen is blank/off. If I unplug the HDMI
connection the system does some display switching and my laptop screen
turns on. When I plug the HDMI connection back in nothing happens. A
couple of xrandr commands later and I can get the HDMI output
displaying how it was originally. Suppose though that instead of
issuing the xrandr commands to bring the external HDMI connection back
up after plugging it in, I reboot the machine instead. Since my
/etc/xorg.conf is unchanged I would expect that both my external
monitors come up, however, the laptop screen comes on instead of my
HDMI external connection which is now shown as disconnected. To get
things back the way they were I can either used xrandr like previously
or the ATI gfx menu options. Note that this only happens with regards
to my HDMI connection because I think the laptop screen and the HDMI
share the TMDS graphics hardware ( Assuming my understanding of these
things is correct ; ) .) Unplugging the VGA doesn't create any auto
switching response.

So, with that said:

Is is xrandr that does the auto switching from ext. HDMI to laptop
automatically when HDMI monitor signal is lost? Or is that the gfx
drivers or some other X program? ( I'd like to disable it if possible

Is it xrandr that is saving some kind of persistent configuration
settings somewhere that overrides my xorg.conf file at the next
reboot? I couldn't find any sort of conf file anywhere related to
this. Googling xrandr info doesn't show much except same man pages.

Is xrandr scheduled to replace xorg.conf altogether? I've noticed that
my xorg.conf really is pretty much as minimal as you can get. In
previous Linux systems I've had much more intricate xorg.conf files
with a lot more details filled in. Other than loading the driver for
the gfx card, it seems like everything else can be pretty much done
through xrandr. Am I understanding correctly where xrandr is headed in
the Linux/X world?


On Sat, Oct 30, 2010 at 4:03 AM, Jeremy Huddleston
<jeremyhu at freedesktop.org> wrote:
> This would be a good place...
> On Oct 29, 2010, at 21:07, Pedro DeKeratry wrote:
>> Hi everyone,
>> Is this the appropriate place to ask questions about the xrandr
>> command line utility in order to understand how it interacts with my
>> system environment at large or is such a question better suited to a
>> distro specific mailing list?
>> --Pedro
>> _______________________________________________
>> xorg at lists.freedesktop.org: X.Org support
>> Archives: http://lists.freedesktop.org/archives/xorg
>> Info: http://lists.freedesktop.org/mailman/listinfo/xorg
>> Your subscription address: jeremyhu at freedesktop.org

More information about the xorg mailing list