Separate X Screens - possible on Intel Integrated HD Graphics?

[Ken Taylor]

On 01/18/2016 09:29 AM, Simon McVittie wrote:
> On 17/01/16 16:49, Ken Taylor wrote:
>> On 01/17/2016 10:05 AM, rhkramer at gmail.com wrote:
>>> On Sunday, January 17, 2016 08:10:38 AM [Michal] wrote:
>>>> The usual pattern is that people ask about multiple screens but do not
>>>> really want them. Having multiple screens only limits what you can do
>>>> and gives you no meaningful benefits.
>>> On some of the industrial (process control) systems I've been
>>> responsible for,
>>> we put up to 4 monitors (with different displays) driven by one
>>> computer in
>>> front of a single operator.
> Multiple heads/outputs/monitors do not have to imply multiple X11
> 'screens'. They can, but they don't have to, and it's very rare to
> prefer multiple screens.
>
> 'Screen' is a jargon term in this context, like 'display' - I'm putting
> it in quotes to be unambiguous. If all your applications run with
> DISPLAY=:0, or equivalently DISPLAY=:0.0, you have one X11 'screen',
> potentially outputting to multiple monitors. If some of your
> applications run with DISPLAY=:0.1 and are permanently tied to a
> different set of monitors (probably a set of size 1), *that* is a second
> X11 'screen'.
>
> If you have multiple LCD/CRT/whatever monitors on one desk, or a laptop
> and a monitor, or a laptop and a projector, the option that is usually
> preferred is a single X11 'screen' spanning multiple monitors, with
> optional runtime switching between mirroring (same content on each
> output) and non-mirroring (different content on each output). That's
> what Xrandr normally does on modern systems, and as far as I'm aware,
> what all current desktop environments optimize for. It's also the X11
> equivalent of all the supported arrangements in Windows and OS X.
>
> For instance, on the laptop where I'm typing this (with Intel HD
> graphics, as it happens), here's what my output looks like:
>
> |----------|
> | monitor  ||--------|
> |          || laptop |
> |----------||--------|
>
> DISPLAY :0 --- screen :0.0 /-- HDMI2 --- monitor
>                             \-- LVDS1 --- laptop
>
> The equivalent with multiple 'screens':
>
> DISPLAY :0 /-- screen :0.0 --- HDMI2 --- monitor
>             \-- screen :0.1 --- LVDS1 --- laptop
>
> would mean I wouldn't be able to drag windows to and from the laptop, or
> copy and paste between the two screens, and I don't have enough
> historical X11 knowledge to know whether I'd need a second keyboard and
> mouse for that setup.
>
>>> I have to admit that the Linux / X window (and successor) terminology
>>> confurses me--when I say multiple screens, I mean multiple monitors
>>> driven by
>>> a single PC and different content on each, and, ideally (but not
>>> always the
>>> case) the ability to move content between displays and copy and paste
>>> to and
>>> from each.
> It sounds as though rhkramer may be one of the people Michal is thinking
> of, who has been confused by the unfortunate historical terminology,
> does want multiple monitors, but does not necessarily want multiple of
> the historical X11 construct whose jargon term is 'screen'.
>
>> I appreciate the vote of confidence.  Perhaps "separate X screens" is
>> something which only a small percentage of user are multi-tasking enough
>> to take advantage of. However, I am one of them.
>  From other emails, it sounds as though you (for disambiguation: Ken) are
> one of the minority that genuinely does want multiple X11 'screens',
> with no copy/paste between them, and no ability to move windows between
> them. I'm not sure how this actually improves your experience when
> multi-tasking when compared with a Xrandr-style large 'screen' spanning
> multiple monitors, but "you asked for it/you got it"[1].
>
> However, this is a sufficiently small minority that it seems reasonable
> to ask "are you *sure* this is really what you're looking for?" when
> someone asks for it, because it's fairly common for people who are
> confused by the terminology to think they want multiple (jargon)
> 'screens' for their multiple (non-jargon) screens, even though that
> leads to reduced functionality.
>
> If your goal is to have immovable displays appearing on particular
> monitors, that's also possible to achieve within a single 'screen' by
> modifying or configuring a window manager or compositor to place windows
> where you want them. (For instance, tiling window managers like
> Awesome[2] tend to support this sort of thing.)
>
Thanks Simon,

I don't think this is really as complicated as you make it appear. If 
you will look at the last option on this page 
http://jsmylinux.no-ip.org/basic-information/dual-monitors/ titled 
"Individual Panels" that is what I setup on my Nvidia card when I first 
got the PC and two monitors in 2009 (Ubuntu 9.10). In 2010 I switched to 
CentOS 6 due to an issue with Ubuntu 10.04 LTS. I have been running 
CentOS 6 ever since.   CentOS 6 uses Gnome 2 (this works with Mate on 
CentOS 7 as well) and the tweaking involved:

1 - Setup separate X screens as shown on the referenced page using 
nvidia-config.

2 - The only anomaly I found with Gnome 2 (same with Mate) is that the 
icons on the Gnome panels on the left monitor (screen0) were 
duplicated.  This is easy to resolve.  Delete and add back each 
launcher, menu or whatever to the panel. The issue never re-occurred in 
5 years.

3 - Create two new panels at the top and bottom of the right monitor 
(screen1). Add the desired menus, launchers etc. to these panels.

4 - Enjoy!

I can NOT drag a window between monitors - True.

I CAN copy/paste text, files, etc. from an application on one monitor to 
an application on the other monitor.

I can run multiple instances of most applications independently by 
simply selecting the launcher from the panel on the monitor on which I 
wish to see the application. For example I have my "normal" Firefox 
profile called by the launcher on the left monitor.  As part of my 
nightly data backup process I make a copy of this profile. The Firefox 
launcher on the right monitor calls the backup profile - thus I have all 
but the latest bookmarks etc. available on the right monitor (some 
privacy benefits as well but that is beyond the scope of this discussion).

My left monitor - pivoted vertical - usually has Thunderbird running in 
the top half and a VMWare virtual machine running in the bottom half. I 
use this to run a specially configured copy of Firefox to access secure 
email on protonmail.ch.  At the moment I have Firefox running on the 
host and accessing the above referenced page - it is showing in the 
lower half of the screen - under Thunderbird and I can scroll it without 
loosing focus from Thunderbird.

I have a bash terminal and vinagre (remote desktop viewer) on the first 
workspace of the right monitor - connected to a Mint Mate machine which 
I am configuring.  workspace 2 is running another virtual machine, 
workspace is running vlc so I can play some music as I work - do not 
want to be tripping over vlc and Nautilus pointed to my music library 
when Alt-Tab-ing between windows on the first workspace. And I am not 
doing much right now.

Bottom line... I setup the separate X screens when I first was able to 
connect two monitors.  I have gotten used to the feature and have 
adapted my work processes to it. Can I do it on Intel graphics? was just 
an experiment as I had the little micro PCs with two video outputs.

Time to take a break - my step-son just called. I have to go fix some 
sort of malware issue on his Windoze PC :-)

Ken