LinuxQuestions.org
Visit Jeremy's Blog.
Go Back   LinuxQuestions.org > Forums > Linux Forums > Linux - Desktop
User Name
Password
Linux - Desktop This forum is for the discussion of all Linux Software used in a desktop context.

Notices


Reply
  Search this Thread
Old 11-07-2019, 06:19 PM   #1
chripy811
Member
 
Registered: Mar 2017
Posts: 31

Rep: Reputation: Disabled
kvm switch - force display config to stay connected even when monitor disconnected


I am having a problem with a kvm switch i bought, it works but with 1 problem

I currently have multi-monitors, and when i am using the kvm switch my display settings looks like this, which is correct


display-min.png
https://imgur.com/Tfdc67R



but when i press the kvm button, the first monitor goes away, like below


display2-min.png
https://imgur.com/0hjyu60


which is not a problem because i am not using that computer anymore,


then when i press the kvm switch button again to go back to the orignal desktop, my display settings revert to 2 monitors, which is great


display-min3.png
https://imgur.com/FMnKJMH


which is great, now i can go back to working on my computer



but....




i added more monitors, and it works fine, the 1 monitor always go away and comes back when i press the kvm button


the problem is , when i add more monitors(4 monitors, 2 top, 2 bottom),
that 1 monitor has some sort of glitch after coming back from kvm
the applications(such as firefox or file explorer) stick to edge of the monitor window(monitor 1), it only happens on 1 monitor 1, the monitor which the kvm is hooked up too,

my display settings mess up because the kvm makes the monitor disconnect and my display settings must configure itself back to 4 monitors

i tried,

sudo service lightdm force-reload
sudo service lightdm restart

and it reloads the display settings but it closes all of my applications almost like i logged in and out,
the displays are back to normal and no glitch, but it closed all my applications which is annoying


does anyone what is happening?

the only solutions i can think of is:

1) is there a way i can force the display settings configuration to stay unchanged even if i unplug a monitor or press the kvm button,

2) or is there a way i can refresh lightdm without it "logging in and out"
Attached Thumbnails
Click image for larger version

Name:	display-min.png
Views:	37
Size:	66.7 KB
ID:	31789   Click image for larger version

Name:	display2-min.png
Views:	37
Size:	64.4 KB
ID:	31790   Click image for larger version

Name:	display-min3.png
Views:	37
Size:	66.7 KB
ID:	31791  

Last edited by chripy811; 11-07-2019 at 06:21 PM.
 
Old 11-07-2019, 10:31 PM   #2
frankbell
LQ Guru
 
Registered: Jan 2006
Location: Virginia, USA
Distribution: Slackware, Ubuntu MATE, Mageia, and whatever VMs I happen to be playing with
Posts: 15,541
Blog Entries: 25

Rep: Reputation: 4504Reputation: 4504Reputation: 4504Reputation: 4504Reputation: 4504Reputation: 4504Reputation: 4504Reputation: 4504Reputation: 4504Reputation: 4504Reputation: 4504
Are all these monitors the same make/model?

The first thing I would do is change the order of the monitors (move them to different leads on the KVM switch) to see whether the problem follows the troublesome monitor to its new location in the sequence. This will prove whether the culprit is inside or outside the monitor itself.
 
Old 11-07-2019, 10:39 PM   #3
mrmazda
Senior Member
 
Registered: Aug 2016
Location: USA
Distribution: openSUSE, Debian, Knoppix, Mageia, Fedora, others
Posts: 1,838

Rep: Reputation: 573Reputation: 573Reputation: 573Reputation: 573Reputation: 573Reputation: 573
Note I'm neither a LightDM user nor a KVM user. It seems like you may be expecting too much using a KVM in conjunction with that many displays. All that said:

I would expect you can force enabling of each individual monitor via video= options on the kernel cmdline:
https://www.kernel.org/doc/Documentation/fb/modedb.txt

Another option should be to use /etc/X11/xorg.conf* to manually configure your displays. Getting it right this way can be quite daunting. It might be slightly easier to use xrandr in a hotkey and/or startup script to do the same. Either of xorg.conf or xrandr routes might need to force enabling via video= cmdline.
 
Old 11-08-2019, 03:55 PM   #4
jefro
Moderator
 
Registered: Mar 2008
Posts: 19,290

Rep: Reputation: 2957Reputation: 2957Reputation: 2957Reputation: 2957Reputation: 2957Reputation: 2957Reputation: 2957Reputation: 2957Reputation: 2957Reputation: 2957Reputation: 2957
My guess right now is either get a KVM that supports a keep alive in that range or set video adapters so that they don't know the display. ???
 
Old 11-08-2019, 09:05 PM   #5
chripy811
Member
 
Registered: Mar 2017
Posts: 31

Original Poster
Rep: Reputation: Disabled
Quote:
Originally Posted by frankbell View Post
Are all these monitors the same make/model?

The first thing I would do is change the order of the monitors (move them to different leads on the KVM switch) to see whether the problem follows the troublesome monitor to its new location in the sequence. This will prove whether the culprit is inside or outside the monitor itself.


It's not the monitor. I changed it to a different monitor and it happens on that monitor also. It follows the monitor.

The monitors are all different models and make




Quote:
Originally Posted by mrmazda View Post
Note I'm neither a LightDM user nor a KVM user. It seems like you may be expecting too much using a KVM in conjunction with that many displays. All that said:

I would expect you can force enabling of each individual monitor via video= options on the kernel cmdline:
https://www.kernel.org/doc/Documentation/fb/modedb.txt

Another option should be to use /etc/X11/xorg.conf* to manually configure your displays. Getting it right this way can be quite daunting. It might be slightly easier to use xrandr in a hotkey and/or startup script to do the same. Either of xorg.conf or xrandr routes might need to force enabling via video= cmdline.


isn't xorg.conf only for nvidia? I am using amd,

I tried with nvidia cards but they were giving me much more hassle, and amd is much more user friendly







Quote:
Originally Posted by jefro View Post
My guess right now is either get a KVM that supports a keep alive in that range or set video adapters so that they don't know the display. ???
i can't find any keep alive on ebay,






the reason i am using a dvi kvm switch is that, if i want to use both desktops on dvi, as my other desktop is a gaming pc


i tried using vga but the resolution and colors is not as great as when using dvi

so currently i am forced to use 1 desktop on vga and they other on dvi


the solution is simple, i will have to purchase a new monitor, one monitor 2 outputs(without vga), for example, a monitor with dvi and display port
then that will solve my problem, my current monitor is 13 years old


but i really wanted to use the kvm switch, since i bought it, now it's useless,
linux works great with 2 or 3 monitors,

but when using 2 videos cards and more than 3 monitors, it has glitches,

i never had that problem with windows, but going back to windows is not an option

Last edited by chripy811; 11-08-2019 at 09:13 PM.
 
Old 11-08-2019, 09:51 PM   #6
jefro
Moderator
 
Registered: Mar 2008
Posts: 19,290

Rep: Reputation: 2957Reputation: 2957Reputation: 2957Reputation: 2957Reputation: 2957Reputation: 2957Reputation: 2957Reputation: 2957Reputation: 2957Reputation: 2957Reputation: 2957
I assume that DDC and EDIC are fully supported in displays and video cards. So that would be something that needs to be known.
Then you'd need a KVM that stores each while switching.

We have an old XP connected to two RH servers and we use a script to monitor the change and run correct display. Guess it could be done in linux.
 
Old 11-09-2019, 03:14 AM   #7
mrmazda
Senior Member
 
Registered: Aug 2016
Location: USA
Distribution: openSUSE, Debian, Knoppix, Mageia, Fedora, others
Posts: 1,838

Rep: Reputation: 573Reputation: 573Reputation: 573Reputation: 573Reputation: 573Reputation: 573
Quote:
Originally Posted by chripy811 View Post
isn't xorg.conf only for nvidia? I am using amd
Xorg.conf* is for admin/systemwide overrides to Xorg defaults and automagic. It can be used for any GPU supported by Xorg.

NVidia's proprietary X drivers generally work best overriding some defaults.
 
Old 11-11-2019, 12:49 AM   #8
connectpro_rexwu
LQ Newbie
 
Registered: Mar 2017
Posts: 2

Rep: Reputation: Disabled
Thumbs up Multi-monitor video keep alive KVM switches

Yes, you're conclusion of the issues is correct. You need to find KVM switches support Full-Time EDID feeding no matter if connected monitors are on-off after the initial connections to the KVM switch.

You can find the "DDM class KVM switches". There are some limited makers still making DVI version of DDM class KVM switches.


Rex
 
  


Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off



Similar Threads
Thread Thread Starter Forum Replies Last Post
[SOLVED] wi-fi forever disconnected? (I can't get it to stay not soft blocked...) soullessbeta Linux - Newbie 3 12-28-2015 06:23 PM
[SOLVED] "No KVM, No qemu-kvm" Available error while trying to install KVM on CentOS 6.3 sriramdas Linux - Virtualization and Cloud 5 01-01-2013 11:46 AM
KVM on Redhat 5.7: KVM can ping outside network, outside network can't ping KVM svandyk Linux - Networking 1 09-23-2011 07:45 AM
[Debian/Qemu/KVM] Why qemu --enable-kvm works but not kvm directly? gb2312 Linux - Virtualization and Cloud 2 03-21-2011 03:05 PM
Wi-Fi won't stay disconnected / Very promiscuous networking fhsm Linux - Networking 1 01-13-2009 05:00 PM

LinuxQuestions.org > Forums > Linux Forums > Linux - Desktop

All times are GMT -5. The time now is 10:04 AM.

Main Menu
Advertisement
My LQ
Write for LQ
LinuxQuestions.org is looking for people interested in writing Editorials, Articles, Reviews, and more. If you'd like to contribute content, let us know.
Main Menu
Syndicate
RSS1  Latest Threads
RSS1  LQ News
Twitter: @linuxquestions
Facebook: linuxquestions Google+: linuxquestions
Open Source Consulting | Domain Registration