Linux - HardwareThis forum is for Hardware issues.
Having trouble installing a piece of hardware? Want to know if that peripheral is compatible with Linux?
Notices
Welcome to LinuxQuestions.org, a friendly and active Linux Community.
You are currently viewing LQ as a guest. By joining our community you will have the ability to post topics, receive our newsletter, use the advanced search, subscribe to threads and access many other special features. Registration is quick, simple and absolutely free. Join our community today!
Note that registered members see fewer ads, and ContentLink is completely disabled once you log in.
If you have any problems with the registration process or your account login, please contact us. If you need to reset your password, click here.
Having a problem logging in? Please visit this page to clear all LQ-related cookies.
Get a virtual cloud desktop with the Linux distro that you want in less than five minutes with Shells! With over 10 pre-installed distros to choose from, the worry-free installation life is here! Whether you are a digital nomad or just looking for flexibility, Shells can put your Linux machine on the device that you want to use.
Exclusive for LQ members, get up to 45% off per month. Click here for more info.
UPDATE: Solved Setting up 4 Monitors. Here is a pic: Multi Screen Pic. FYI the wallpaper is a big orange Flower.
Hi, I hope someone can help me out. I am having trouble setting up 4 monitors in Centos5. I have searched some threads and have tried some of the solutions but I must be missing something in my xorg.conf file.
I have two DualHead video cards installed. At the moment the system is running fine on 2 monitors and I am spanning the desktop over the 2 monitors. The other 2 monitors on the other video card are not displaying anything. My goal is to span the desktop over all 4 monitors.
The monitors are laid out 2x2 or 2 over 2.
Here is my xorg.conf file...
# Xorg configuration created by system-config-display
Here's a quick thing for you to try, based on how I used Xinerama. Your above serverlayout section (I quoted) is configured (incorrectly I think) to place 2 of your displays on top of or under 2 of the other ones. Not what you want, because you can't see the ones UNDER the other ones. I mean to say, the displays appear to be laid over each other.. Try this:
.. to lay the screens out in a horizontal line, left to right. If you want as you say to have a 2 and 2 layout, try this:
Screen 0 "Screen0" 0 0
Screen 1 "Screen1" 1680 0 # this is 1680 pixels to the right (x+1680)
Screen 2 "Screen2" 0 1050 # this one is 1050 pixels lower (y+1050)
Screen 3 "Screen3" 1680 1050 # this is x+1680 AND y+1050
The offsets affect the horizontal and vertical position of the top left corner of any given display. Adjust as required, depending on which screen(s) you have where in your 2+2 layout.
Now, that said, normally one would use metamodes with Xinerama, to define the display resolutions. Using MetaModes IS optional; however, if the above does not work, then you might need to use 'MetaModes' lines with offsets, to achieve the same results.
For example, in your 'screen' sections for lets say Videocard0 and videocard1 (which are the same card in this example) you might have something like:
Note that each of these is basically the reverse of the other, because each section describes ONE of the outputs of the card, relative to the OTHER output. Looks redundant, but provides clarity to the X server and helps you debug things such as which card-connector is screen 0 and screen 1, and which is on the left or the right, etc..
For the second videocards connectors, it would be the same idea, but with CRT-2 and CRT-3.
P.S> I can't recall right off if MetaModes lines are 'Option' lines (like Option "MetaModes" "blah blah.."), or just go as is, without the word 'Option'. You may want to look that up.
P.P.S> Is 'Viewport' necessary? I didn't look up what it does, but if you aren't sure if you need it, try commenting it out. I've never needed it, and didn't find it did anything noticeable either :S -- just a thought
Please let us know if this helps
Last edited by GrapefruiTgirl; 09-16-2007 at 06:13 PM.
Reason: Clarity & detail
Thanks alot! I was wondering what the 0 0 was doing. I thought it might be XY but never tried setting it. I'll give it a shot and let you know how it goes...
So then I tried is to use the other card (PCI:13:4:0) on it's own and configured xorg.conf just like I did for card (PCI:12:6:0) and had no luck with that either. I should mention that when I tried this the other card (PCI:12:6:0) remained in it's PCI slot but I made no reference to it in the xorg.conf file.
Here is the xorg.conf file I tried to use with card PCI:13:4:0
##########################################################
# Xorg configuration created by system-config-display
##########################################################
(II) Primary Device is: PCI 12:06:0
(II) ATI: Candidate "Device" section "Videocard0".
(II) ATI: Candidate "Device" section "Videocard1".
(WW) RADEON: No matching Device section for instance (BusID PCI:12:6:0) found
(WW) R128: No matching Device section for instance (BusID PCI:12:6:0) found
(II) ATI: Shared PCI/AGP Mach64 in slot 13:4:0 detected.
(EE) ATI: XF86Config Device sections "Videocard0" and "Videocard1" may not be assigned to the same adapter.
(EE) No devices detected.
1 - Looks like it wants you to use the primary (12:6:0) adapter (maybe first, or maybe ONLY)
2 - Based on the (EE) errors you posted, the machine or the X server seems to think that the card it is seeing is unable to do dual-headed output.
Is there a setting in your BIOS for "Primary VGA card priority" or something like that, which allows you to choose either AGP, PCI, or PCI-E as the first choice for the video adapter?
Is this an SLI board? Or, if not, what kinds of slots are the cards in? Like, a PCI & a AGP, or a PCI-E and a PCI, or what? And what motherboard is it? Perhaps it isn't capable of running two cards, though I wouldn't know either way what if any motherboards will and won't run two cards. I thought it wouldn't be an issue. I get the impression from the fourth (II) message that the AGP and PCI are a shared bus, in which case, you **might** not be able to put two cards on it.
FWIW, that file you posted looks fine. I can't see any reason it wouldn't work.
Bizarre..
Last edited by GrapefruiTgirl; 09-22-2007 at 08:48 PM.
The 2 cards are in PCI-X slots, not to be confused with PCI-E. It is a Dell 2600 server that has 6 of these PCI-X slots that are backwards compatible with PCI cards.
Here is an interesting thing that happened when I moved the cards into some different slots. My first card layout was a card in slot 6 and another card in slot 4. When I ran lspci the output was:
So now this has got me confused even more, I think that one card is supposed to have 2 controllers so I should have 4 in total, at least this is what I am guessing? Both of these cards are exactly the same make and model with 1 DVI and 1 VGA port on them. If I have just one card plugged in I get 2 VGA controllers, one for a Radeon and one for a Rage. (I am guessing Radeon is for the DVI and Rage is for the VGA)
So then I tested each card on it's own and they are both working fine so I don't think there is a defect in any of the cards.
Then I tried making a 2 screen conf file to use both 0c:06.0 and 0c:07.0 and I ended up with 2 seperate desktops which is fine with me but I couldn't move my mouse out of the first desktop screen. Is there some setting that allows your mouse to move over all screens?
So I think there is no problem running dual-head cards. I think the problem is that it wants to use that primary card only. And I don't understand why moving the cards around gave me 3 VGA controllers?
Tonight I am going to try moving the cards into slot 1 and 2 and look into the BIOS. If that doesn't do it then i am out of ideas...
Wow, this is definitely an interesting situation. Why the sad face though you're getting *somewhere* at least!
What appears obvious, and I think you have noticed it too, is that different slots must have different capabilities.
When you posted this:
Code:
Then I moved the cards around to have them in slot 5 and 6 and ran lspci again and got:
0c:06.0 VGA compatible controller: ATI Technologies Inc Radeon RV100 QY [Radeon 7000/VE]
0c:07.0 VGA compatible controller: ATI Technologies Inc Radeon RV100 QY [Radeon 7000/VE]
0d:04.0 VGA compatible controller: ATI Technologies Inc Rage XL (rev 27)
I got the impression that 06.0 and 07.0 are the card in slot 6 (just guessing).
What I would do, would be to leave that card in place and configure X to run both heads, and THEN, when that works, I would try the second card in EACH of the other slots you have available, and keep checking lspci until you hopefully see both heads of the second card. Then, proceed to alter your X configuration to enable the two heads, thereby giving you all 4 heads.
I'm again no expert with IRQ lines and pci-sharing, but you might look into the IRQ sharing setups in the BIOS, and make sure, if possible, that whichever slots you have the cards in are NOT sharing any interrupt lines. That might help.
As for the mouse being able to travrese both screens, I have never had trouble with this. What might be needed would be to add the line Option "Xinerama" "1" to each SCREEN section, which tells the X server that those screens are the Xinerama ones, thereby connecting them together. If you cannot get it to work with Xinerama, try using TwinView in place of Xinerama. I use nVidia, so the ATI setup may be slightly different, but the xorg.conf man page, along with the docs for the driver you are using, should explain any needed options for Xinerama and Twinview with your drivers.
I also have in my KDE desktop properties, a section for configuring how the Xinerama or Twinview display operates; things like screen wrapping, mouse traversal from one to the other, and other things. Perhaps you have a similar area in your desktop environment (assuming you are even using a desktop environment on this server board) where you can set desktop properties like these.
I wouldn't think that the slot used would influence how the card operates, especially considering that all the slots are of the exact same type, and the cards are the same too.
Worth checking if you can reserve or specify a particular different IRQ for each card though.
As to why the cards are appearing as they do in lspci, that's very odd indeed. Maybe you would learn something if you physically examine both cards, and check the numbers and codes stamped on the GPU chips on the cards themselves. Maybe they aren't as identical as they look?
It's the embedded VGA... what threw me off was lspci saying "ATI Technologies Inc" just like the cards say.
So I have removed any mention to it in the conf file and I am now able to 2 monitors to work on either card but still can't get all 4 to go at the same time.
BTW with 2 monitors going the first monitor has the desktop icons and taskbar while the second monitor has nothing. Is this the expected behavior? My wallpaper is stretched out over the 2 of them though which is nice. In the end if I ever get these 4 going would it be the same scenario with the first monitor having the icons and taskbar and the wallpaper streched out over all 4?
Quote:
Originally Posted by GrapefruiTgirl
Yes, the PCI slots often share IRQs in pairs.
I noticed that.. should I have both cards sharing the same IRQ? Or should I move them onto different IRQs?
I feel close to a solution. I am glad to see that I can put 2 monitors to work on either card. I was worried that perhaps the board didn't support it. Although I have noticed that the graphics are a little slower with one of the cards?
I really appreciate your feedback... if you ever come to Ottawa I'll buy you a beer!
Here is the conf file I am using now but like I say only Screen0 and Screen1 are working...
##########################################################
# Xorg configuration created by system-config-display
##########################################################
Screen 0 "Screen0" 0 0
Screen 1 "Screen1" 1680 0 # this is 1680 pixels to the right (x+1680)
Screen 2 "Screen2" 0 1050 # this one is 1050 pixels lower (y+1050)
Screen 3 "Screen3" 1680 1050 # this is x+1680 and y+1050
InputDevice "Keyboard0" "CoreKeyboard"
Option "Xinerama" "on"
Option "Clone" "off"
EndSection
OK so I found out why this controller shows up:
0d:04.0 VGA compatible controller: ATI Technologies Inc Rage XL (rev 27)
It's the embedded VGA... what threw me off was lspci saying "ATI Technologies Inc" just like the cards say. Aha! LOL, that's an onboard vidfeo device is it? Quite the full-featured motherboard!
So I have removed any mention to it in the conf file and I am now able to 2 monitors to work on either card but still can't get all 4 to go at the same time.
Right, so two monitors will work on EITHER card, one at a time, in ANY slot? But just not BOTH cards in two slots at one time... ok...
BTW with 2 monitors going the first monitor has the desktop icons and taskbar while the second monitor has nothing. Is this the expected behavior? My wallpaper is stretched out over the 2 of them though which is nice. In the end if I ever get these 4 going would it be the same scenario with the first monitor having the icons and taskbar and the wallpaper streched out over all 4?
Yes, this is normal behaviour, and it would likely be the same with all 4 screens going. At one point I had my taskbar stretched across two monitors, and it was a pain in the a$$, so I think it's practical having the taskbar on the main monitor you use (monitor 1 so to speak), and mind too, you can download custom wallpapers, some very nice ones, designed for multiple displays. I haven't seen any long enough for a line of 4 screens, but I bet with some patience, you could make a fantastic wallpaper for a 2x2 setup by mirroring a two-screen wallpaper from the top two monitors onto the lower two
I noticed that.. should I have both cards sharing the same IRQ? Or should I move them onto different IRQs?
Just a somewhat educated guess: I would say they should have separate interrupt lines.
I feel close to a solution. I am glad to see that I can put 2 monitors to work on either card. I was worried that perhaps the board didn't support it. Although I have noticed that the graphics are a little slower with one of the cards?
I can't explain this. Do you mean, when you use card A in a slot, the performance differs from when you have card B in the same slot? If so, I'm not sure what to say there. No clue at all. LOL, lets get them WORKING first, and THEN worry about fine-tuning them
I really appreciate your feedback... if you ever come to Ottawa I'll buy you a beer!
Sounds great! I was there a few weeks back, so who knows, maybe I'll get there again before the next ice age!
Here is the conf file I am using now but like I say only Screen0 and Screen1 are working...
OK, the file itself looks great. Far as I can tell, and to the best of my knowledge, it is laid out fine and **should** work. We're either missing something, or haven't learned something that we need to know --- yet!
How about, with both cards plugged in, and using the file you posted there, start X and have a look at the x log file (/var/log/xorg.0.log) and see what if anything it says about the two cards? Maybe there's a clue there...
I am finding this thread informative for my own use as well, for a few reasons:
1 - I have 3 monitors plus a TV, but my nVidia 7100GS only runs any two displays at a time, so I have had to make an xorg.conf with dual server-layouts in it, so when I want to switch to the TV, a click a button and it goes from running two monitors, to using one monitor and a TV.
2 - I just got hold of a ATI junky-old PCI card when I gave my last nvidia card to my roomie. Now, with her old ATI card, I am working on running my dual setup as
A) three monitors, and..
B) The switch to TV mode will run two monitors, plus the TV.
and 3 - I have sn SLI motherboard, and at some point, I hope to have a second 7100GS for the second PCI-E slot, to run all 3 monitors PLUS the TV, all at once.
So, it's great if my help gets you set up how you want, and it's also keeping me on my toes -- there's something to be learned every day, using Linux.
Hey, here's a thought.. Any chance the BIOS offers a place to "Disable the Onboard VGA device"??
It might be using an IRQ that we could be using.
If not possible, then it may be best to assign it in xorg.conf, like name it and identify it, but just don't USE it in any Screen sections.
At least that way, we'd know that it's not getting inadvertently mixed into what you're trying to do..
Hit may be best to assign it in xorg.conf, like name it and identify it, but just don't USE it in any Screen sections.
At least that way, we'd know that it's not getting inadvertently mixed into what you're trying to do..
OK I did that... just before I did it I was lloking into the log file.
Here is an interesting line:
(WW) RADEON(0): Direct Rendering Disabled -- Dual-head configuration is not working with DRI at present.
Please use the radeon MergedFB option if you want Dual-head with DRI.
This is in the log as well... but the conf file I am using clearly has the sections?
(II) Primary Device is: PCI 05:04:0
(WW) RADEON: No matching Device section for instance (BusID PCI:12:7:0) found
(WW) RADEON: No matching Device section for instance (BusID PCI:13:4:0) found
(EE) Screen 2 deleted because of no matching config section.
LinuxQuestions.org is looking for people interested in writing
Editorials, Articles, Reviews, and more. If you'd like to contribute
content, let us know.
