HOWTO: Get Dual Monitor Display Working - Ubuntu 8 / Hardy Heron

[mhenwood]

I had come hardships getting dual display working between by laptop (Dell Vostro 1700) running Hardy Heron, and an extra LCD panel display.

I noticed in these forums that others had similar problems, so here are my successful steps for those in similar pain.

FIRSTLY, read this: http://www.intellinuxgraphics.org/dualhead.html
It really will help.

If you come this far without reading the above link, you'll probably get it wrong.

Next MAKE SURE YOU BACKUP YOUR EXISTING xorg.conf!
sudo cp /etc/X11/xorg.conf /etc/X11/xorg.conf.backup

These instructions assume you have a laptop to the left of your larger LCD panel, and that you want the LCD panel to be the main screen. If this isn't true, you need to pay attention to the "LeftOf" / "RightOf" options in step 3 below, also in step 4 and during the rejigging of the layout using xrandr (more on this below).

Before you start, you will need the ID of your displays from xrandr. Do:
sudo xrandr -q

In my case, the displays are called "VGA" and "LVDS". You will need these values when doing step 1 below.

Edit your xorg.conf (from the out-the-box Heron dist version) and make the following changes:
1. In 'Section "Device"', add the 2 lines highlighted in red so the section reads like this:
Section "Device"
Identifier "Configured Video Device"
Option "monitor-VGA" "lcddisp"
Option "monitor-LVDS" "laptop"
EndSection

Note that the "Option" keys are the 2 values you got in 'sudo xrandr -q' earlier, prefixed bu the string "monitor-". THIS IS IMPORTANT!

2. Change the identifier in 'Section "Monitor"' as shown in red, so it reads like this:
Section "Monitor"
Identifier "lcddisp"
EndSection

3. Immediately below the existing 'Section "Monitor"' add a new 'Section "Monitor"' which looks like this:
Section "Monitor"
Identifier "laptop"
Option "LeftOf" "lcddisp"
EndSection

N.B. This assumes your laptop is to the left of your lcd display. If not, change "LeftOf" to "RightOf".

4. In 'Section "Screen"', edit the Monitor to be the one you want as your main screen (in my case 'lcddisp' but you may want 'laptop'):
Section "Screen"
Identifier "Default Screen"
Monitor "lcddisp"
Device "Configured Video Device"
EndSection

5. Also in the same 'Section "Screen"' add a SubSection as follows:
Section "Screen"
Identifier "Default Screen"
Monitor "lcddisp"
Device "Configured Video Device"
SubSection "Display"
Depth 24
Modes "1680x1050" "1440x900"
Virtual 3120 1050
EndSubSection
EndSection
Note: The Modes options should reflect the 2 modes of your laptop and LCD panel (or just one mode if they are the same resolution.)
Also Note: Virtual setting. You should calculate this such that the first figure is the TOTAL width of both displays added together, and the second figger is the larger of the 2 display heights. If you don't know the resolutions you can get them by:
sudo xrandr -q

In short, the Virtual section creates a giant virtual screen which must be big enough to hold the 2 screens we are physically using.

OK that's the xorg.conf edited, so....

6. Restart X (CTRL-ALT-BACKSPACE)

Nothing amazing will have happened yet; you now need to use xrandr to move the displays around in the giant virtual screen we just made:

7. sudo xrandr -q to get the system names of the 2 displays. Im my case these are VGA (the LCD panel) and LVDS (the laptop)

8. Whichever display you opted for on the right, now use xrandr to reposition it. In my case:
xrandr --output VGA --pos 1440x0

This moved my VGA (lcd) display to position 1440, which is exactly at the right hand edge of my laptop display (within the giant virtual screen.)

This should have done the trick.

Again, this document is very helpful:
http://www.intellinuxgraphics.org/dualhead.html

Good Luck!

[shr2004]

First, thanks a lot your post. It is a good tutorial for dual screen. I am new in Ubuntu. In Hardy Heron, I found that in the System>Preferences there is an option for changing resolution which can be used to configure dual monitor. For my case it can detect my extra LCD along with laptop and I can fix its resolution. But to use both laptop and LCD monitor together, the active resolution becomes the LCD's resolution which is larger than laptop's, as a result the bottom pan is not visible in laptop screen. As I occasionally use extra LCD, I turn-off laptop display and use extra LCD. That works fine for me. Is your method works dynamically, ie, you can add or remove extra display without running any configuration, then I will try that.
Thanks

[mhenwood]

Yeh, sorry I wasn't that clear about how to source the monitor names, so maybe it wasn't too clear.

Please re-read the above post - point(1) and the paragraph above.

Basically it's not dynamic but it does allow you to address both screens seaprately (so you don't have the problem with 2 displays with the same resolution setting, when one screen is physically smaller)

[SteveG]

mhenwood,

Thank You for a great HowTo. I was working with dual monitors in ver 7.04. I decided to upgrade to 8.04 ubuntustudio (new install - no change in hardware) & just couldn't get the same dual working. All the how-to's just were not addressing the problems. I even tried the ATI catalyst drivers . no go.

I actually went out and bought a nvidia to replace the ati, till I decided to check the help one last time.
I now have dual display with a big desktop- as per your instructions. Though the size might need to be adjusted, i think. The background image of the mixer - gained in size.


My video is a ATI x300 pcie
Dual LG L194WTX at 1440x900 Virtual at 2880x900

Super Thanks
SteveG

[RAOF]

It might be worth noting that the Virtual line here:

...
5. Also in the same 'Section "Screen"' add a SubSection as follows:

Section "Screen"
        Identifier      "Default Screen"
        Monitor         "lcddisp"
        Device          "Configured Video Device"
        DefaultDepth    24
        SubSection "Display"
                Virtual 3120 1050
        EndSubSection
EndSection

...

is really the only necessary part of these modifications. The virtual line specifies the maximum combined resolution available across all of your screens, and it defaults to the resolution of the highest resolution device you have plugged in when X starts. This means that by default you can't do non-clone dual-head.

However, once you have a specified a (sufficiently large) Virtual size, you can use System->Preferences->Screen Resolution to dynamically handle dual-head. It will also restore your dual-head settings when you log in. That's the way I have my dual-head set up on my laptop, since I tend to swap things around a lot.

[sharifi14]

Hey guys,

I'm a newbie to Linux so a lot of this sounds pretty alien to me. Basically, I want to clone the picture on my primary display (15 inch 16:9) onto a secondary display (7 inch 16:9). Here's a bit of background information...

To set up my dual display, I've been using the nvidia-settings GUI, as opposed to editing X Server in Terminal which many tutorials seem to use.

So far, I've managed to clone the picture of the primary display onto the secondary display. However it is not scaled correctly, i.e. only a quarter (if that) of the desktop is showing.

Would anybody be able to offer any thoughts on (preferably using nvidia-settings) how to change the resolution of the secondary display to show all of the contents?

I apologise in advance for any ignorance that this post may exude, but I look forward to hearing back from someone!

Alex

[EDIT: I've worked out how to change the brightness - it was the display afterall...]

[Motorhead Kaze]

Thanks for this post, I just bought my new monitor yesterday, and am excited to get the split screen/extended desktop going. I am running an ATI Radeon dual-head graphics card on Hardy, with 2, 19in. monitors (off my desktop).Before I follow the above instructions, I have questions. Here they are:

  Section "Screen"
Identifier "Default Screen"
Monitor "lcddisp"
Device "Configured Video Device"
SubSection "Display"
Depth 24
Modes "1680x1050" "1440x900"
Virtual 3120 1050
EndSubSection
EndSection

Are these numbers, which I have in red, good for everyone or do I need to use a specific pair for my machine?

Next, to RAOF, 'SubSection "Display" Virtual 3120 1050 EndSubSection... is really the only necessary part of these modifications.' does this mean that this is the only part of xorg.conf I need to change to get one elongated desktop/split screens? Not sure if that is what you meant.

Also, since I am running two similar monitors (VGA-0 and DVI-0) off a desktop, I want to know if in this section:

Option "monitor-VGA" "lcddisp"
Option "monitor-LVDS" "laptop"

should I be writing this instead?

Option "monitor-VGA" "lcddisp"
Option "monitor-DVI" "lcddisp"

Thank you for taking time to deal with my lack of understanding. I just want to make sure I get all the parts correct before I do it.

Peace

[RAOF]

Thanks for this post, I just bought my new monitor yesterday, and am excited to get the split screen/extended desktop going. I am running an ATI Radeon dual-head graphics card on Hardy, with 2, 19in. monitors (off my desktop).Before I follow the above instructions, I have questions. Here they are:

  Section "Screen"
Identifier "Default Screen"
Monitor "lcddisp"
Device "Configured Video Device"
SubSection "Display"
Depth 24
Modes "1680x1050" "1440x900"
Virtual 3120 1050
EndSubSection
EndSection

Are these numbers, which I have in red, good for everyone or do I need to use a specific pair for my machine?

You want the numbers in red to be greater than or equal to the combined maximum resolution of all monitors you intend to plug in. So, I've got a 1680x1050 laptop and a 1280x1024 LCD screen; I'd want the Virtual line to be greater than or equal to 2960 1050 (= 1680+1280 1050) in order to have the two screens side-by side, or >= 1680 2074 (= 1680 1050+1024) to have one on top of the other. Setting a Virtual size larger than you need will consume a little more VRAM than strictly necessary. Note that some cards (some Intel cards, I believe) will lose 3D acceleration with a Virtual size too high - this threshold seems to be when either of the dimensions exceed 2048.

Next, to RAOF, 'SubSection "Display" Virtual 3120 1050 EndSubSection... is really the only necessary part of these modifications.' does this mean that this is the only part of xorg.conf I need to change to get one elongated desktop/split screens? Not sure if that is what you meant.
...

Exactly. Once you've set the Virtual size, you can use System->Preferences->Screen Resolution to manage your multiple monitors - cloning, above, below, beside, etc. You don't need to hardcode the layout in the xorg.conf.

[Motorhead Kaze]

Thanks for replying!

Just another question. My xorg.conf looks like this:

Section "Device"
	Identifier	"Configured Video Device"
	Driver		"fglrx"
EndSection

Section "Monitor"
	Identifier	"Configured Monitor"
EndSection

Section "Screen"
	Identifier	"Default Screen"
	Device		"Configured Video Device"
	Monitor		"Configured Monitor"
	SubSection "Display"
		Modes		"800x600"
	EndSubSection
	Defaultdepth	24
EndSection

and I am now wondering if (under "Monitor") I need to change the words "Configured Monitor" to "lcddisp" ? Or is it ok like it is?

I tried this:

Modes "1280x1024" "1280x1024"
Virtual 2560 1024

My current resolution on either screen is 1280x1024. But after saving xorg.conf I went up to System->Preferences->Screen Resolution and tried changing from cloned output, but after ticking off that box and playing with left/right, not only did that not work (cloned output came back on), when I restarted X, I got a Gnome settings daemon error, and Gnome was all wacked out. The desktop image is about 2 inches lower than usual, my keyboard keys are all set back to American standard (I usually have it set on Japanese keyboard) and etc. I changed back to my original settings on xorg.conf, but Gnome is still messed. What did I do wrong?

...what? Ok, 5 seconds after I pressed "Save" on this post, Gnome came back.

As for the xorg.conf, was I mistaken to type in the above ratios? Should I have typed 800x600 twice, then under virtual something like 1600 600? Or is my problem that my numbers are identical? (you guys are using external screens that are different in size from your laptops) I am a bit confused.

[Motorhead Kaze]

Howdy again.

Well, after following the way I mentioned above, and nothing good happened, I re-read the full tutorial above, and read the Intel tutorial 2 more times. This is what I did in my xorg.conf, and nothing happened. I even tried going back into the screen resolution menu to try to arrange things, but after messing with that, I reopened it just to check, and the clone box is checked again. Here is my xorg.conf:

Section "Device"
	Identifier	"Configured Video Device"
	Driver		"fglrx"
	Option "monitor-VGA" "lcddisp"
	Option "monitor-DVI" "Configured Monitor"
EndSection

Section "Monitor"
	Identifier	"lcddisp"
EndSection

Section "Monitor"
Identifier "Configured Monitor"
Option "LeftOf" "lcddisp"
EndSection

Section "Screen"
	Identifier	"Default Screen"
	Device		"Configured Video Device"
	Monitor		"Configured Monitor"
	SubSection "Display"
		Modes	"1280x1024"
	Virtual 2560 1024
	EndSubSection
	Defaultdepth	24
EndSection

After restarting X I put this in a terminal

 xrandr --output VGA --pos 1280x0

This should be right now, correct? But I still have two of the same screen going on here. So what is not working?

Your help would really be appreciated.

PS Are the names "lcddisp" and "Configured Monitor" not ok? "lcddisp" I copied from the text above. If this monitor actually has a proper name, how do I find it? Should I not be using the name "Configured Monitor" anymore?

Help.