USB to DVI DisplayLink with OpenSUSE 12.2 and KDE with xrandr / KRandR

English Hardware
1

I have recently purchased a USB to DVI DisplayLink module for the purposes of having a 3rd monitor connected to my Dell Latitude D630 Laptop. I have used several sites to try and get it working with only partial success.

Here are a couple of sites that have good info but I can’t seem to apply the info appropriately for my purposes:
Four DisplayLink USB graphics adapters with udlfb and fbdev under Linux - YouTube
https://wiki.archlinux.org/index.php/DisplayLink
DisplayLink on Fedora Linux

When I plug in the device into the monitor and the USB port it seems to be activating at the kernel level as I do get the green screen that says it has activated. Here is my dmesg output:

[22837.652318] usb 1-3.2: device descriptor read/64, error -32
[22837.828902] usb 1-3.2: New USB device found, idVendor=17e9, idProduct=0199
[22837.828913] usb 1-3.2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[22837.828920] usb 1-3.2: Product: USB Adapter
[22837.828926] usb 1-3.2: Manufacturer: DisplayLink
[22837.828931] usb 1-3.2: SerialNumber: 1650000222
[22837.991964] udlfb: DisplayLink USB Adapter - serial #1650000222
[22837.991971] udlfb: vid_17e9&pid_0199&rev_0108 driver's dlfb_data struct at ffff88014b4b7000
[22837.991975] udlfb: console enable=1
[22837.991978] udlfb: fb_defio enable=1
[22837.991980] udlfb: shadow enable=1
[22837.992370] udlfb: vendor descriptor length:22 data:22 5f 01 0020 05 00 01 03 04 02
[22837.992372] udlfb: DL chip limited to 2080000 pixel modes
[22837.992445] udlfb: allocated 4 65024 byte urbs
[22837.992542] usbcore: registered new interface driver udlfb
[22838.010617] [drm] Initialized drm 1.1.0 20060810
[22838.022561] usbcore: registered new interface driver udl
[22838.073555] udlfb: 1280x1024 @ 60 Hz valid mode
[22838.073561] udlfb: 720x400 @ 70 Hz valid mode
[22838.073565] udlfb: 640x480 @ 60 Hz valid mode
[22838.073569] udlfb: 640x480 @ 75 Hz valid mode
[22838.073572] udlfb: 800x600 @ 60 Hz valid mode
[22838.073575] udlfb: 800x600 @ 75 Hz valid mode
[22838.073579] udlfb: 1024x768 @ 60 Hz valid mode
[22838.073582] udlfb: 1024x768 @ 75 Hz valid mode
[22838.073586] udlfb: 1280x1024 @ 75 Hz valid mode
[22838.073590] udlfb: 1152x864 @ 75 Hz valid mode
[22838.073593] udlfb: 1280x1024 @ 60 Hz valid mode
[22838.073597] udlfb: Reallocating framebuffer. Addresses will change!
[22838.075298] udlfb: 1280x1024 @ 60 Hz valid mode
[22838.075302] udlfb: set_par mode 1280x1024
[22838.079875] udlfb: DisplayLink USB device /dev/fb1 attached. 1280x1024 resolution. Using 5120K framebuffer memory

This tells me that it should be good to go and is ready to be used but the KRandR screen configuration doesn’t show it as an option.

My next course of action is that I need to put something in the xorg.conf file that declares this as a device or a monitor or something but this seems to make my X not start up. I had this placed in my 50-device.conf file with unsuccessful results:

Section "Device"
  Identifier "DisplayLinkDevice"
  Driver "displaylink"
  Option "fbdev" "/dev/fb1"
EndSection

Any assistance on this would be great.

2

Here are a few other supplemental links for your reading:

When I plug in the device into the monitor and the USB port it seems to be activating at the kernel level as I do get the green screen that says it has activated. Here is my dmesg output:

[22837.652318] usb 1-3.2: device descriptor read/64, error -32
[22837.828902] usb 1-3.2: New USB device found, idVendor=17e9, idProduct=0199
[22837.828913] usb 1-3.2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[22837.828920] usb 1-3.2: Product: USB Adapter
[22837.828926] usb 1-3.2: Manufacturer: DisplayLink
[22837.828931] usb 1-3.2: SerialNumber: 1650000222
[22837.991964] udlfb: DisplayLink USB Adapter - serial #1650000222
[22837.991971] udlfb: vid_17e9&pid_0199&rev_0108 driver's dlfb_data struct at ffff88014b4b7000
[22837.991975] udlfb: console enable=1
[22837.991978] udlfb: fb_defio enable=1
[22837.991980] udlfb: shadow enable=1
[22837.992370] udlfb: vendor descriptor length:22 data:22 5f 01 0020 05 00 01 03 04 02
[22837.992372] udlfb: DL chip limited to 2080000 pixel modes
[22837.992445] udlfb: allocated 4 65024 byte urbs
[22837.992542] usbcore: registered new interface driver udlfb
[22838.010617] [drm] Initialized drm 1.1.0 20060810
[22838.022561] usbcore: registered new interface driver udl
[22838.073555] udlfb: 1280x1024 @ 60 Hz valid mode
[22838.073561] udlfb: 720x400 @ 70 Hz valid mode
[22838.073565] udlfb: 640x480 @ 60 Hz valid mode
[22838.073569] udlfb: 640x480 @ 75 Hz valid mode
[22838.073572] udlfb: 800x600 @ 60 Hz valid mode
[22838.073575] udlfb: 800x600 @ 75 Hz valid mode
[22838.073579] udlfb: 1024x768 @ 60 Hz valid mode
[22838.073582] udlfb: 1024x768 @ 75 Hz valid mode
[22838.073586] udlfb: 1280x1024 @ 75 Hz valid mode
[22838.073590] udlfb: 1152x864 @ 75 Hz valid mode
[22838.073593] udlfb: 1280x1024 @ 60 Hz valid mode
[22838.073597] udlfb: Reallocating framebuffer. Addresses will change!
[22838.075298] udlfb: 1280x1024 @ 60 Hz valid mode
[22838.075302] udlfb: set_par mode 1280x1024
[22838.079875] udlfb: DisplayLink USB device /dev/fb1 attached. 1280x1024 resolution. Using 5120K framebuffer memory

This tells me that it should be good to go
You have both the old udlfb and the newer (buggy) DRM/KMS udl loaded.

and is ready to be used but the KRandR screen configuration doesn’t show it as an option.
And it won’t – randr currently doesn’t work across Screens or Displays. (* more on this in a moment)

My next course of action is that I need to put something in the xorg.conf file that declares this as a device or a monitor or something but this seems to make my X not start up. I had this placed in my 50-device.conf file with unsuccessful results:

Section "Device"
  Identifier "DisplayLinkDevice"
  Driver "displaylink"
  Option "fbdev" "/dev/fb1"
EndSection

Any assistance on this would be great.

  • you are calling the “displaylink” driver but then passing an option that pertains to the (modified for displaylink devices) “fbdev” driver
  • I doubt that either of these drivers is available natively from stock openSUSE … meaning you’ll have to either find them from OBS or grab them from their git repos
  • the presence of the DRM/KMS udl driver, as mentioned above, is likely impacting
  • no doubt your xorg configuration is incomplete

Linking to my “* more on this in a moment” comment", be aware of how these devices are (because of technical limitations) currently setup under Linux – as either a separate Screen within the existing Display, or as a new separate Display. Inherent with both of those configurations is another set of problems associated with usability. See my post here: https://forums.opensuse.org/english/get-technical-help-here/hardware/478678-not-getting-multi-monitor-work-new-workstation-need-help-stat-please.html#post2488920 as it indirectly provides some background.

You will have to set up an xorg configuration to reflect the route you chose to go.

3

Tyler_K, thanks for the info. It will take a bit for me to digest this information and make an attempt at getting this to work. I am looking at a couple of ideas right now. Since I use the additional displays only at the office, I am thinking of using the 2 X server setup this way I can execute it only when needed. I got this from: DisplayLink - Gentoo Wiki

This wiki says to create a file called xorg.conf.DL under /etc/X11/ which doesn’t seem like how the Xorg is setup anymore. So, I am thinking that I should create an X config file called 60-displaylink.conf and place it in /usr/share/X11/xorg.conf.d/

And it won’t – randr currently doesn’t work across Screens or Displays. (* more on this in a moment)

My confusion on this is that I use the KrandR for configuring two displays and it seems to work quite well. Is the issue that it doesn’t work with different display devices?

After reading through your post explaining the multi-monitor setup, it does sound like a challenge. What I didn’t understand is why did you set Xinerama to be “off?” Wouldn’t that allow for the cursor and windows to move between display devices?

My likely first attempt will be to set this up as a separate X but to be honest, this confuses me a bit too. If it is a separate X does that mean I have to open a separate session of KDE? Also, with this setup, does this mean I will not be able to move open windows from one X session to the other?

Perhaps you can help guide me based on my needs:
I am running the 3rd monitor specifically for the purpose of working with spreadsheets and PDFs, nothing fancy but a larger desktop would make me more efficient, for sure.

Your help is much appreciated.
-Nathan

4

I effectively borked my system quite nicely by making this modification:

I added a file called “50-displaylink.conf” under /etc/X11/xorg.conf.d/ and put in it this information:

Section "Device"
    Identifier "DisplayLinkDevice"
    driver "fbdev"         # Or fbdev depending on what you installed
    Option "fbdev" "/dev/fb1"    # You have to use the correct framebuffer device here
EndSection

Section "Monitor"
    Identifier "DisplayLinkMonitor"
EndSection

Section "Screen"
    Identifier "DisplayLink Screen"
    Device "DisplayLinkDevice"
    Monitor "DisplayLinkMonitor"
    SubSection "Display"
        Depth 16         # 24bit works fine but for USB 2.0 a lot of data
        Modes "1280x1024"
    EndSubSection
EndSection

Section "ServerLayout"
    Identifier "Server Layout"
    Screen 0 "DisplayLink Screen" 0 0
    Option "AllowMouseOpenFail" "True"
    InputDevice "Keyboard0" "CoreKeyboard"
    InputDevice "Mouse0" "CorePointer"
EndSection

Section "ServerFlags"
    Option "AllowEmptyInput" "false"
    Option "AutoAddDevices" "false"
    Option "AutoEnableDevices" "false"
EndSection

Section "InputDevice"
    Identifier "Keyboard0"
    Driver "void"
EndSection

Section "InputDevice"
    Identifier "Mouse0"
    Driver "void"
EndSection

I ran this command to get it going:
startx – :1 -config /etc/X11/xorg.conf.d/

xauth:  file /home/wolfnf/.serverauth.4128 does not exist


Fatal server error:
Cannot move old log file "/var/log/Xorg.1.log" to "/var/log/Xorg.1.log.old"


Please consult the The X.Org Foundation support 
         at http://wiki.x.org
 for help. 

xinit: giving up
xinit: unable to connect to X server: Connection refused
xinit: server error
-------------------------------------------------------------------------------------------
xinit failed. /usr/bin/Xorg is not setuid, maybe that's the reason?
If so either use a display manager (strongly recommended) or adjust /etc/permissions.local

So, I ran it as root and it killed display :0 and effectively disabled my keyboard and mouse, presumably because of the “void” driver but it looked great! When I rebooted my system, only the DisplayLink unit activated and not the internal video card. So, I had to reboot to terminal and remove that 50-displaylink.conf out of the directory to get my system to boot normally.

I’ll continue to work on it…

5

You can still use xorg.conf, or your own filename or the conf.d files for that matter… there are just several ways to go about things now

[quote="“futureboy”]

My confusion on this is that I use the KrandR for configuring two displays and it seems to work quite well. Is the issue that it doesn’t work with different display devices?[/quote]You’re missing the point – the monitors you are configuring via Krandr are within a single Screen. Re-read my other post again. And take care to differentiate between what is being discussed – for example, I use “Screen” and “Display or DISPLAY” when talking about specific X related concepts, as opposed to colloquial language which often uses monitor/panel/screen/display/any_other_name_for_thing_with_pictures_on_it interchangeably

After reading through your post explaining the multi-monitor setup, it does sound like a challenge. What I didn’t understand is why did you set Xinerama to be “off?” Wouldn’t that allow for the cursor and windows to move between display devices?
I don’t like the inherent drawbacks of xinerama. In a case of

  • a single X Display, with a Single Screen: mouse and windows move across all monitors
  • a single X Display, with mulitple Screens: mouse moves freely across Screens, windows are confined to moniors of the Screen upon which they were launched
  • multiple X Displays: mouse can not move across Displays. Nor can windows. Above conditions of above two cases apply

Window migration can be achieved (to a degree) via software like Xpra/winswithc.
Mouse cursor migration can be fully achieved via synergy and a few lessor others (x2x. x2VNC…)

My likely first attempt will be to set this up as a separate X but to be honest, this confuses me a bit too. If it is a separate X does that mean I have to open a separate session of KDE?
Yes, doing it in this manner, you will have a seperate login. You don’t have to use KDE – add whatever DE you want (GNOME, Xcfe, …). If you do use the KDE, I’d suggest logging in under another account then your user account.

Also, with this setup, does this mean I will not be able to move open windows from one X session to the other?
That is correct (see above)

On another note, if you set it up as a separate Screen within the same X Display, you could use a different WM (window manager) on it if you wished … or just use kwin

6

Just some quick comments:

  • The “Screen 0” in the ServerLayout section – while “0” is indeed technically correct, IIRC using a “0” here might throw off X cause it associates it with Screen 0 of the primary Display/X server … just drop it for safe measure
  • The void driver, on its own, doesn’t prevent the evdev driver from attaching a k/b and mouse to the layout. However, disabling the AutoAddeDevices option (as shown) should surppress it… the side affect of that, however, is that it disables all hotplugging on that server/Display
  • you can move the options to ServerLayout section if you wish … or have a serverflags section if you so desire … the other way is just a little clearner (IMO)
  • on a pedantic note, you should change the mouse and k/b designations to "1"s as you are setting up the second X server/Disiplay, and “0” should be assigned to devices on the primary server/Display

I ran this command to get it going:
startx – :1 -config /etc/X11/xorg.conf.d/
…
Yes, you can’t startx as user any more.

So, I ran it as root and it killed display :0 and effectively disabled my keyboard and mouse, presumably because of the “void” driver but it looked great! When I rebooted my system, only the DisplayLink unit activated and not the internal video card. So, I had to reboot to terminal and remove that 50-displaylink.conf out of the directory to get my system to boot normally.

I’ll continue to work on it…
Yeah, I kind of think that was caused by the Screen 0 listed in the ServerLayout section. Drop that and try again.

Do note, however, that doing a startx as root can end up messing up a lot of permissions on your user account. Not particularly advised unless you know your way around the system… (that said, I do use it myself for testing purposes, but I do know what it can break, and do know how to recognize problems that doing so might typically have caused, and finally how to fix them lickedy split … as opposed to spending days in user forums trying to figure out why audio doesn’t work right any more or…"

7

I do feel a little silly in my confusion now with the screen and monitor declarations. Correct me if I’m wrong but “screen,” as it is defined in the Xorg is quite literally the virtual space that one display device can push and the “monitor” declaration is the window into that virtual space. So, randr can only define one “screen” which is tied to a “device” at a time as of right now.

Before I make another attempt, as I can only put an hour or so here and there to this little project, I think I need to better communicate what my desired end result is. I want to be able to go from home, with just my single monitor laptop, then go to work, and dock into having two additional monitors with minimal configuration times between the two states. I want to be able to move windows around to each display and I would prefer to run just one session of KDE (negotiable point, not absolutely required). I am looking for a simple and efficient setup. I have no issue with writing a script that I execute when docked or undocked to activate and deactivate the third display. What I don’t want to do is manually fiddle around with the xorg config files every time my system changes states.

I realize that a seamless, shiny solution is not likely, but I would like to minimize the time I go from sitting down and docking my computer, waking it up to being fully operational. So, from your expert view point, which method would likely best serve me: a one or two X Server setup and what, if any, solution would you recommend to be able to achieve some kind of window migration between all displays.

Your time and help is very much appreciated.

8

Hmm, somewhat accurate.

First, a graphics adapter device can also have its (output) heads segregated info separate Screens, or, for that matter Displays.

For example, say you have just one graphics adapter device with two outputs (DVI, VGA, or whatever), and its pci id is 1.00.0. Typically the two heads on the adapter (and the monitors attached to them) would be bound to the same Screen (Screen0), which would reside within the X Server Display (Display0). But if you wanted to have two Screens within one X server Display you’d do (this is just rough):


Device section
id card0
driver blah 
busid 1:00:0
end

Device Section
id card1
driver blah
busid 1:00:0
end

Monitor section 
monitor0
end

monitor section
monitor1
end

Screen section
id Screen0
device card0
monitor monitor0
end

Screen section
id Screen1
device card1
monitor monitor1
end

ServerLayout section
id layout_for_single_X
Screen 0 Screen0 ...
Screen   Screen1  Northbynorthwest of Screen0
end

Or, if you wanted to have two X server Displays, all you’d have to do is break apart the ServerLayout section and turn it into:

ServerLayout section
id layout0
Screen 0 Screen0 
Input Devices
end

ServerLayout section
id layout1
Screen Screen1
Input Devices
end

One way to conceptualize it is: think of an X server Display as a galaxy – somewhat vague is dimension (how do you nail down where a galaxy starts and ends?). But what we do know is that the Display/galaxy is filled or comprised of Screen(s)/solar system(s) …and each Screen/solar system is in turn comprised by monitior(s)/planet(s) and other heavenly bodies like moons/input devices (k/b, mouse…).

Screens do have a precise Virtual dimension (and note, its always rectangular). But the monitors within the Screen do not have to fill that virtual space (see the link to my prior posting where I gave the conceptual diagram of the one Screen comprised of 3 monitors (M’s) in an L configuration and a dead space (I used “V” to denote that, though, in hindsight, probably should have used “D” … in any regard, together those four characters ( M M M V/D ) fill out the entire virtual space of the Screen)

Now, as for randr, it can only operate (slash: do its magic) upon the monitors within one Screen, and so you can’t simultaneously configure those residing outside a particular Screen. You are free, of course, to configure those other monitors with xrandr by passing the appropriate command; for example: “xrandr -display :1 --screen 83 —output DisplayPort-0 blah blah blah” … Note: 83 is just a gross exaggeration

Before I make another attempt, as I can only put an hour or so here and there to this little project, I think I need to better communicate what my desired end result is. I want to be able to go from home, with just my single monitor laptop, then go to work, and dock into having two additional monitors with minimal configuration times between the two states. I want to be able to move windows around to each display and I would prefer to run just one session of KDE (negotiable point, not absolutely required). I am looking for a simple and efficient setup.
You won’t be able to do that just yet – likely about a year from now yes, this should get simple. But now, your stuck with the current limitations.

have no issue with writing a script that I execute when docked or undocked to activate and deactivate the third display. What I don’t want to do is manually fiddle around with the xorg config files every time my system changes states.
Once you get it set up once, you likely will have no need for fiddling with xorg config … I don’t recall if I’ve linked this is this thread, but it would be appropriate to do so now: xkcd: X11

I realize that a seamless, shiny solution is not likely, but I would like to minimize the time I go from sitting down and docking my computer, waking it up to being fully operational. So, from your expert view point, which method would likely best serve me: a one or two X Server setup and what, if any, solution would you recommend to be able to achieve some kind of window migration between all displays.

Your time and help is very much appreciated.
Hmm, a choice between two evils. Its late and I’m pretty tired right now, so I’m going to have to come back to this one.

9

Great news, I have something that is sort of working but the reality is, I don’t know what I’m doing. Here’s what I changed:

I put the 50-displaylink.conf file in it’s own directory, just in case I had to hard reboot my system:

/etc/X11/xorg.conf.dl

Than I made the changes to the file as you suggested, in the ServerLayout sectioned I removed the “0”

Next I created a script with this:

startx -- :1 -config /etc/X11/xorg.conf.dl/50-displaylink.conf -novtswitch -sharevts -audit 0 vt12 &
sleep 5
x2x -east -from :0 -to :1 &

I ran it as root and KDE started automatically with user root.

How would I go about having it automatically open up any other user?

I am certainly not committed to having a separate X server, I’m just playing with the thing and this is the current rabbit I’m chasing.

Thank you again for your help.

10

Just as an update to my two X server setup.

I can’t initiate the second X server display successfully with sudo, the x2x fails to detect display :0

x2x - error: can not open display :0

I tried to run just the x2x while logged in as root I get this error:

x2x - error: can not open display :1

The only way I can get the second display to open and be usable is to run that script entirely as root user in a terminal.

When I log out on the second X server desktop, it shuts all of display :1 off to include x2x, so that is good to know but have discovered two quarks that are irritating: First, my laptop display dims to minimum periodically and second, the mouse pointer cannot enter a region of the 2nd X server right-most 1/16th and upper-half portion of that screen. None of which are show stoppers.

Despite what I’ve read about the USB to DVI Out adapters, this does a fine job of being able to display videos, even at full screen, sure it’s not perfect but for my purposes it works quite well. It really is much better than I expected. I do wonder, however, how much it is taxing the USB bus. Is there any way of determining that?

I am still very open to other options in initiating the DisplayLink video adapter. I just happen to have a working setup right now and I’m mostly pleased.

11

Good to read – you’re well on the road to success now!

Here’s what I changed:

I put the 50-displaylink.conf file in it’s own directory, just in case I had to hard reboot my system:

/etc/X11/xorg.conf.dl

Than I made the changes to the file as you suggested, in the ServerLayout sectioned I removed the “0”
okay

Next I created a script with this:

startx -- :1 -config /etc/X11/xorg.conf.dl/50-displaylink.conf -novtswitch -sharevts -audit 0 vt12 &
sleep 5
x2x -east -from :0 -to :1 &

I ran it as root and KDE started automatically with user root.

How would I go about having it automatically open up any other user?

There is probably a couple of ways to go about it, but likely the most robust would be go about setting up via the Display Manager – in essence, what you are doing is setting up a static multiseat: https://forums.opensuse.org/english/get-technical-help-here/install-boot-login/479385-multiseat-systemd.html#post2495049

I am certainly not committed to having a separate X server, I’m just playing with the thing and this is the current rabbit I’m chasing.
Well, now that you’ve gone down that hole Alice*, err, futureboy, I’d say its a pretty good route. I think that (though it is more complicated to set up) it is (once it is setup) the more efficient, effective, and capable configuration (in terms of the ability to do “real” work & to be productive).

Off hand I don’t know what would cause those x2x errors … something like that is typically permissions based error … google suggest its to do with the X forwarding or TCP connections.

In any regard, x2x is inferior to synergy … you won’t run into dead space regions … synergy is not difficult to configure. Highly recommend it.

Despite what I’ve read about the USB to DVI Out adapters, this does a fine job of being able to display videos, even at full screen, sure it’s not perfect but for my purposes it works quite well. It really is much better than I expected. I do wonder, however, how much it is taxing the USB bus. Is there any way of determining that?
For a single adapter, for desktop office stuff they are fine. Even for video stuff they are generally fine.

Video games, heavy compositing etc need not apply. Same with adding a whole bunch of adapters – you start to tax the host cpu(s)

Only those pixels that change are compressed and resent … I’d guess that you’d probably see utilization around 5% for office stuff, and probably somewhere along the lines of ~15% for fullscreen video for your res. Open up htop/top on :0 and monitor what it says for usage while you do stuff on :1

I am still very open to other options in initiating the DisplayLink video adapter. I just happen to have a working setup right now and I’m mostly pleased.
Nothing wrong with playing around with it … that’s the only real way to know for sure whether its for you or not.

When you do have your configuration refined a little more, you might then want to look to see whether the other (newer) driver, udl, works or not for you … eventually you will be able to use udl as a DRI2 output slave (whereby the slave adapter (i.e. your displaylink) outputs what is rendered by another adapter (I don’t recall what your system’s primary graphics adaptor is) )

Also have a look at VirtualGL | About / Introduction

12

I should clarify that – for those adapters that have support under Linux … I would be interested in seeing the DL-3xxx chipsets gaining support (as I could make use of a universal dock)

You can see the difference that USB3.0 affords here: 7 Monitors on Windows 7 with USB 3.0

13

It seems I’m stuck. I tried to initiate the X server with xinit instead of startx because I read that someplace but I can’t determine a way to start this X session either as a user without error

Fatal server error:
Cannot move old log file "/var/log/Xorg.1.log" to "/var/log/Xorg.1.log.old"

Is there a way to point the log location to the user directory? I can’t seem to find that anywhere as an option.

You mentioned earlier that it is not a good idea to start two sessions as the same user? I would really like to have both sessions have the exact same permissions. Is there a way to safely start two sessions with the same permissions? Both of which I would prefer to run KDE of course.

Thanks again.

14

Its essentially the same thing (using xinit, as opposed to startx). The error you see is symptomatic of the underlying problem: users can no longer start the X server. For some further background, see: https://forums.opensuse.org/english/get-technical-help-here/install-boot-login/456567-cannot-startx-unless-superuser.html

You mentioned earlier that it is not a good idea to start two sessions as the same user?
Correction – two sessions of the same type (KDE, GNOME…) as the same user. Doing so is asking for havoc to become upon your desktop’s settings (right hand does not necessarily know what left hand is doing). Feel free, on the other hand, to open two different user session types under the same user (though you may have to keep in mind those same concerns on an application level, if you open up multiple instances of the application (across the two Displays), or two of the same session types, with two different users.

I would really like to have both sessions have the exact same permissions. Is there a way to safely start two sessions with the same permissions? Both of which I would prefer to run KDE of course.
Via the DM route.

Thanks again.

15

I’ve browsed a lot of threads and many other forums and I can’t seem to find the answer I need. Since I can’t figure out how to start display :1 to kdm or gdm, I would like to just pass the startx to just open up as a specific user. I tried to pass --login <my username> or -l <my username> but that’s not an option. I and edited “/etc/permissions.local” to uncomment “/usr/bin/Xorg root:root 4711” than ran: “SuSEconfig --module permissions” and tried to startx again as user but that didn’t work either, even with a logout and log back in.

At this point, I would just be happy to initiate display :1 as any user but root, I don’t like having a session of KDE open as root.

Any advice on this is greatly appreciated.

16

I’m working on this project again. I have something that I want to do in my office now. I tried a few other things with no success in getting kdm or gdm to start as opposed to a specific user.

So, my next step to try and get a user to start is to further manipulate the displaylink.sh script and add:

chown $USER /dev/tty12

before

startx -- :1 -config /etc/X11/xorg.conf.dl/50-displaylink.conf -novtswitch -sharevts -audit 0 vt12 &

I was also thinking, to change the location of the logfile to be something like:

/tmp/Xorg.U.log

or something of that nature.

I can’t test this now. I don’t have access to the equipment I wish to test it on.

Any other bits of advice would be greatly appreciated.

Cheers!

17

I haven’t tried it out yet, nor yet know what its working state is like (I just learnt of its existence on Tuesday night) but the new features in RandR v1.4 are a step forward for multiple gpu handling under Linux !

See:
–list-providers
–setprovideroutputsource
–setprovideroffloadsink

 	 	 	[openSUSE-RU-2013:0572-1: xrandr: Update to version 1.4.0](http://lists.opensuse.org/opensuse-updates/2013-04/msg00007.html)
18

I ran this command:

> xrandr --listproviders
RandR 1.4 not supported

Scratched my head and ran this:

> xrandr --version
xrandr program version       1.4.0
Server reports RandR version 1.3

Scratched my head some more. Than checked my NVIDIA version:

319.17

Which is supposed to support RandR 1.4.0. So, I think my next step is to re install my NVIDIA driver to see if that fixes the problem.

19

I re-installed the NVIDIA drivers, no change. Than I checked it on a machine using not the NVIDIA drivers, thinking that NVIDIA drivers might be the problem; same thing.

Any thoughts?

20

Hmmm, not sure … suspect the Xserver is the culprit as opposed to the nvidia … you might want to consider updating the graphics stack: Index of /repositories/X11:/XOrg

I’m going to do some testing with it myself soon (I have a couple of other things on the go right now, that I want to finish up with first before start getting into mucking about with it … I know you know how these things go – i.e. thirty hours after what should have taken just five minutes to complete some task/goal, and you still find yourself banging your head on the table about why the stupid thing won’t work :stuck_out_tongue: … usually to find out shortly later on it was only because you misplaced a comma or spelt something wrong or…