Is ANYONE using separate X screens?

Issues related to hardware problems
taylorkh
Posts: 470
Joined: 2010/11/24 15:08:33
Location: North Carolina, USA

Is ANYONE using separate X screens?

Post by taylorkh » 2016/12/10 15:33:44

On CentOS 6 (Ubuntu 9.10 before that) I am running separate X screens on my two monitors with an nVidia card. I have also run on an ATI card in the past. Each monitor acts independently. That is, if I launch a program from the panel on the left monitor, it displays on the left monitor. If I launch from the panel on the right monitor it displays on that monitor. I can NOT mover applications between monitors - which is fine. Most importantly I can change workspaces INDEPENDENTLY on each monitor.

On CentOS 7... I am having a hard time and it is getting worse. Early in the year I had it working reasonably well. By summer the updates had killed the desktop background on the second monitor (X screen 1) but I could still launch an application from the panel on the monitor and it would run there. I just did another install and regardless of which panel I launch from the program runs on X screen 0.

Here is what I have installed:

CentOS 7 minimal, enabled CR repo and updated
Added epel, elrepo and nux-dextop repos.
yum priorities CentOS 1, elrepo 5, epel 10, nux 15
groupinstall "X Window system"
groupinstall mate-desktop-environment

I am using this configuration on several single monitor systems with great results. On my main dual monitor PC - NOT! I am hoping to find someone ACTUALLY running separate X screens on CentOS 7 successfully. I do not really care about the desktop - simple is better which is why I am running Mate but I am open to something else. HELP! Please!!

TIA,

Ken

ADAMC
Posts: 28
Joined: 2016/12/16 15:55:53
Location: Fort Worth, TX

Re: Is ANYONE using separate X screens?

Post by ADAMC » 2016/12/18 18:19:04

I am using a GeForce GTX 960 and THREE 1080p monitors. The system works as you have described in preference. My desktop spans all three monitors with my Primary monitor on the leftmost monitor. [It can be middle or right if I choose so.] Some programs launch into the monitor where it was last closed...at least for Google Chrome and FireFox. I think most programs will default launch in your Primary monitor. You might look at their launchers, program specific arguments and/or configurations for "mapping" where they start on the one contiguous resolution of all three monitors. Blender for instance will launch by default in one of the other monitors IF you open it, place it and save it as the default user workspace [in Blender] before exiting.

Regardless, I am able to drag, anchor and use applications on the other monitors while launched. Pop-up dialogs for those applications will most likely map to a location relative to a 0,0 graphics origin...aka somewhere on the Primary monitor. In other cases the application developer will map child dialogs/windows relative to the parent window within the application. This I believe is the preference you are seeking. Again, this will probably be specific to each application and not a global setting.

That said, here is how I did it. I am actually using the latest NVIDIA driver "NVIDIA-Linux-x86_64-367.35.run" which I downloaded from the NVIDIA website. And I blacklisted the nouveaux driver. See tips at this link:

http://www.dedoimedo.com/computers/centos-7-nvidia.html

You should also read about nvidiaXineramaInfo or Xinerama options in the xorg.conf file.

BACKUP BACKUP BACKUP your data before starting though.

After you have downloaded the NVIDIA driver, you will need to make it executable. Then restart in console/multi-user.target mode and login as root. [The driver will not run in GUI mode.] Afterwards, reboot in graphical.target mode and you should see all monitors as a span. You can then also launch NVIDIA X Server Settings from Applications>Other>NVIDIA X Server Settings launcher. Once there, look at X Server Display Configuration for further customizing the layout. [This is where you can specify your Primary monitor choice.]

Keep in mind that you will have to boot in console/multi-user.target mode each time the kernel is updated, because the nvidia driver is proprietary. I believe there is a way to correct for this, but I am content to just run it with each new kernel patch. Should I find a way to make this a more permanent scenario, I will post my findings here.

I hope this is helpful. If not, perhaps I do not accurately understand your request.

Cheers,

taylorkh
Posts: 470
Joined: 2010/11/24 15:08:33
Location: North Carolina, USA

Re: Is ANYONE using separate X screens?

Post by taylorkh » 2016/12/18 21:05:03

Thanks ADAMC for the most detailed response. I got a kick out of your
BACKUP BACKUP BACKUP your data before starting though.
:D I have always, since I started using CP/M, kept my OS separate from my data. That makes backup a lot simpler. The data I backup hot. The OS I backup cold with Clonezilla. A great product. For this experimentation I am in fact unplugging my "production" drive and plugging in a test drive. I still backup the test OS so I can recover from whatever I screw up. That said...

I am using the kmod-nvidia package from the elrepo repository. Those folks do a great job packaging the proprietary nVidia code into something which will survive kernel updates etc.

As to your system... How many workspaces do you have? On my CentOS 6 configuration I have 4 on each screen (monitor) and that gives me 4 x 4 or 16 possible permutations. That is the key advantage/requirement. I want to be able to leave one screen (monitor) on workspace 1 and cycle through the workspaces on the other screen (monitor). If ONE desktop spans all three of your monitors I suspect that the workspace changer will change what is displayed on all three monitors together. Is that true?

At to where does something launch... On CentOS 6 the programs launch on the screen (monitor) which contains the panel from which I launch them. If I right click on the desktop and "Open in terminal" the terminal launches on the screen (monitor) on which I clicked. If I right click and "Create" something such as a launcher it ALWAYS creates on screen 0. System dialogs such as Launcher Properties (from an existing launcher) also open ONLY on screen 0. Same for dialogs asking for a root password etc. Other dialogs from most programs open with the program on the same screen in my experience.

Ken

ADAMC
Posts: 28
Joined: 2016/12/16 15:55:53
Location: Fort Worth, TX

Re: Is ANYONE using separate X screens?

Post by ADAMC » 2016/12/18 22:13:52

taylorkh wrote: The OS I backup cold with Clonezilla. A great product.
I have used Clonezilla, but find G4L does a better job backing up/migrating partitions. [Helpful when moving single drives to RAID and/or shrinking partitions from HDD to SSD.] Like with any toolbox, having more than one tool to approach any task is best practice.
taylorkh wrote: I am using the kmod-nvidia package from the elrepo repository. Those folks do a great job packaging the proprietary nVidia code into something which will survive kernel updates etc.
Thanks for the tip.
taylorkh wrote: If ONE desktop spans all three of your monitors I suspect that the workspace changer will change what is displayed on all three monitors together. Is that true?
Yes, such is my situation, but not limited to only 4 workspaces...it is dynamic. I am currently looking at 5 possible workspaces spanning the three monitors and can grow more. I can easily traverse them using the Ctrl+Alt+Arrow combinations. Pumping applications to other monitors left/right with Super+Shift+Arrow(left/right). Or up/down using Ctrl+Alt+Shift+Arrow(up/down). Hence, I have the same functionality. I see now your request though. You are looking at an X server for each monitor...DISPLAY=:0 or DISPLAY=:1, etc. Maybe this will help:

https://www.x.org/wiki/Development/Docu ... Multiseat/

or multi-head system:

https://www.phoronix.com/forums/forum/l ... t-xinerama
taylorkh wrote:At to where does something launch... On CentOS 6 the programs launch on the screen (monitor) which contains the panel from which I launch them.
Yes, that makes sense, because in your case you have an independent X session on each monitor. I get it now. In my case, the programs will launch somewhere on the active workspace across the 3+ monitors. BTW, Virtual Box is another application that remembers its graphical placement once exited. Again, thanks for the tips.

taylorkh
Posts: 470
Joined: 2010/11/24 15:08:33
Location: North Carolina, USA

Re: Is ANYONE using separate X screens?

Post by taylorkh » 2016/12/18 23:00:57

Thanks again ADAMC,

I have seen the page on multi-head before. It reminds me of one of the neatest displays I have ever seen - quite cutting edge in ca. 1985. The company I worked for had just opened a new data center. Three IBM and two Amdahl mainframes. In the "control room" the operators had gas plasma monitors (the glowing orange ones) about 3 feet wide. Each one had FOUR 25 line, 80 column "terminals" displayed. They could navigate between the 4 "windows" (no such thing as Windows back then) and change what was being displayed. Amazing! and no telling how much they cost.

We got the full tour of the place. The fellow giving the tour was AMAZED that water could flow through pipes to cool his IBM machines. He started at the cooling tower and followed the lines to the mainframes and back - pulling up floor tiles as he went. The group I was with all had nuclear power plant experience and two of us were former Navy Machinist Mates. Water, steam and other stuff flowing through pipes? Second nature to us. We thought the computer stuff was neat and were thoroughly amused by the tour guide and his wide eyed excitement when he described flowing water :mrgreen:

Back to the more modern computers... Yes, I know I can have more than 4 workspaces. That is just what happens to be setup at the moment.

I guess I need to look into other display options. When I first got two monitors on one machine - Ubuntu 9.10 - I poked around with the configuration tool. I stumbled on the separate X screen configuration, liked it and stayed with it.

Worse comes to worse when I get my next PC it will be a dual socket workstation with two 6 core (or more) processors and 32 GB of RAM. I will run one X screen and park a virtual machine on each monitor. That way I will be able to flip though workspaces to my heart's content without interfering with the other monitor. Depressing. Perhaps two PCs for two monitors and a KVM switch. Been there, done that but with two PCs and ONE monitor. That thought is REALLY depressing. :lol:

Ken

ADAMC
Posts: 28
Joined: 2016/12/16 15:55:53
Location: Fort Worth, TX

Re: Is ANYONE using separate X screens?

Post by ADAMC » 2016/12/20 00:46:45

:D
Instead of a KVM switch try Synergy. It works quite well across platforms:

https://symless.com/synergy/

Sorry, I could not be more helpful.

Cheers,

taylorkh
Posts: 470
Joined: 2010/11/24 15:08:33
Location: North Carolina, USA

Re: Is ANYONE using separate X screens?

Post by taylorkh » 2016/12/20 19:36:23

Hi ADAMC,

That symless product looks neat. I have no idea how it works but I will dig into it. The one downside I see it that I will need MORE MONITORS! I have my main desktop, two headless servers, a headless OLD desktop made into a server, a Dell micro desktop hooked up to the TV as a media player, a test micro desktop, an ancient netbook serving as an mp3 player out in my shop and the wife's desktop. Except for my desktop and the test machine I access the others with VNC. With symless I might as well give each one it's own monitor :D

Maybe I will pick up a 72" TV for $99 next Black Friday and provide each computer a piece of the realestate. Not sure if the resolution would be sufficient.

So many choices. I need to step back and figure out what I am trying to do in the first place. Thanks again for your encouragement. I will post back if I get something running with symless.

Ken

taylorkh
Posts: 470
Joined: 2010/11/24 15:08:33
Location: North Carolina, USA

Re: Is ANYONE using separate X screens?

Post by taylorkh » 2016/12/20 20:49:16

Hello again ADAMC,

Have you actually used the symless/synergy product? I have been looking around their web site an while it looks neat in concept...

I can not determine:

Does the license cover one server (keyboard & mouse machine) and an unlimited number of clients or is a license needed for each machine?
Do they have a repo for Linux?
What are the dependencies for the .rpm package?

And, it appears I cannot register for their forum to ask these questions until I purchase the software(?)

I shot them the questions and will let you know what they say when they answer.

Ken

ADAMC
Posts: 28
Joined: 2016/12/16 15:55:53
Location: Fort Worth, TX

Re: Is ANYONE using separate X screens?

Post by ADAMC » 2016/12/22 10:04:52

Yes, I have used it. Nick Bolton is the creator of this useful utility. But, only recently has he started charging for its use:

https://symless.com/pricing

I believe this is a one time, lifetime charge for Basic or Pro. I am not sure what they charge for enterprise, which includes Multiple Users. I originally installed it from an .rpm file and that was for Fedora. I do not know what method is used now for installation. I haven't had recent need for it. You may contact them at:

service@symless.com

Happy Holidays to you!

taylorkh
Posts: 470
Joined: 2010/11/24 15:08:33
Location: North Carolina, USA

Re: Is ANYONE using separate X screens?

Post by taylorkh » 2016/12/22 14:33:42

And a Happy Holidays to you ADAMC!!!

I have contacted symless. In response to my questions I was told that the license is for "one user" which I guess means that I can connect as many client computers to my server computer as I wish. They do have .rpm format packages available but not a repository as of yet. I pulled the latest nightly build and ran a yum localinstall on both CentOS 6 and 7. No dependency issues were reported. The main issue I see is how to change my computing paradigm for the better.

In the OLD days I though it was a great thing to be able to run two (at times 3) PCs from the same keyboard, mouse and monitor with a mechanical KVM box. Now with tigervnc, x11VNC and VMWare I can remotely access 7 additional physical machines in my collection and run numerous virtual machines from my single keyboard. Two monitors, separate X screebs run 98% to my liking from a single machine/video card. Two PCs to run two monitors?

Perhaps I should get a couple of thin client boxes, one per monitor then move my computing environments to a server and tie two computing environments together with the symless product so I can use a single mouse/keyboard to access the two thin clients.

More realistically I could put a tiny PC (Dell Inspiron Micro or Intel NUC) on the left monitor which I use for email, web, a place to past text into gedit temporarily from something I am working on on the right monitor and a few occasional minor programs such as operating my scanner. These are all low power requirements except Firefox :-( And if I cannot get my old MFC scanner, printer thing to work in CentOS 7 it might be easier in Ubuntu... Then put my ancient but more powerful i7-860 box on the right monitor for "real" work and tie all of the various filesystems together witih nfs. This is getting ridiculous.

Or I might purchase a new Dell workstation with a 1 year RedHat contract. I can then tell Dell and RedHat to make the damned thing work with separate X screens or take it back. I can take the thing to RedHat HQ which is only about 20 mikes away and jump up and down in their lobby.

Final option - a lobotomy, purchase a tablet and just slide my finger around the screen. I wonder if my medical insurance covers that? :lol:

I have come close to throttling clients and co-workers who would come up to my desk eating a bag of potato chips and proceed to "point" to things on my screen and leave a trail of greasy fingerprints. My blood pressure has gone up 12 points just thinking about it :x Nice to be retired!

Back to reality... I have started compiling a list of to-dos before I can move to CentOS 7. Things like getting my MFC printer driver to work and connecting it to the scanning utility. I need to get working on this as support for CentOS 6 runs out in less than 4 years :mrgreen:

Thank you again for pointing me to that really neat software. I am not sure it is the solution but it is too neat to ignore. I will have to do something with it.

Ken

p.s. I did not have these problems when I was running CP/M.

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