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-   -   Dual Monitors - but identical images! (https://www.linuxquestions.org/questions/linux-newbie-8/dual-monitors-but-identical-images-895991/)

rmhandlinux 08-06-2011 10:32 PM

Dual Monitors - but identical images!
 
I have not run Linux/Unix for several years. I have installed Red Hat Enterprise (free demo) on my old desktopm and it runs. I have added a second monitor, as there two video cards installed. I get two identical screens in spite of trying 'Individual Desktops' and also 'Spanning Desktops' under Display Settings-Dual Head. Reboots don't help. (Sorry, I'm using Gnome). I want the 'Extend desktop' effect u-know-who offers.

Thanks.

Tinkster 08-07-2011 01:02 AM

Hi, welcome to LQ!

Quote:

Originally Posted by rmhandlinux (Post 4435680)
I want the 'Extend desktop' effect u-know-who offers.

Thanks.

Slackware?! :}

Sorry, just kidding. Which graphics chipset are you using in that machine?



Cheers,
Tink

EDDY1 08-07-2011 01:04 AM

Tinkster OP is using demo can you install anything in demo as redhat is not free?

Tinkster 08-07-2011 01:47 AM

Quote:

Originally Posted by EDDY1 (Post 4435725)
Tinkster OP is using demo can you install anything in demo as redhat is not free?

I wouldn't have a clue. If he's using a dualhead intel chipset, however, he
won't need to install anything.



Cheers,
Tink

rmhandlinux 08-07-2011 12:12 PM

Answering Tinkster
 
(Is this the right way to annswer?)

System-Administration-Display reports that BOTH cards are "ATi Technologies Inc Radeon RV100 QY (Radeon 7000/VE". I doubt that is correct: the output plugging options are visibly different, and I seem to be getting only 800 X 600.

It seems to me the problem is not video chips (the screens look fine), but what linux is choosing to send down the wires. Does that make sense?

EDDY1 08-07-2011 12:16 PM

How long is the demo good for as Redhat is not free, but I believe Centos is the free version of Redhat.
I would install Centos and have a fully functional version. Then you may be able to get the dual-monitor setup without configuring.

Tinkster 08-07-2011 12:25 PM

Quote:

Originally Posted by rmhandlinux (Post 4436047)
(Is this the right way to annswer?)

System-Administration-Display reports that BOTH cards are "ATi Technologies Inc Radeon RV100 QY (Radeon 7000/VE". I doubt that is correct: the output plugging options are visibly different, and I seem to be getting only 800 X 600.

It seems to me the problem is not video chips (the screens look fine), but what linux is choosing to send down the wires. Does that make sense?

Not sure I follow your logic; it's all important which hardware
you're using because it determines whether or not you can easily
enough do the "extended desktop" thing or not. Looking at your
post, and googling for it with linux and dual-head thrown in
gives a few hits: this one, while geared at Ubuntu, seems
quite promising.



Cheers,
Tink

adamk75 08-07-2011 03:39 PM

Bring up a terminal and show us the output of 'xrandr'.

Adam

paulmarc 08-08-2011 04:38 AM

Redhat Dual Screens with ATI CCC
 
Update: As adamk75 stated, the VGA card Radeon 7000 is not supported by the current ATI driver.

I was able to have dual screens (with spanning desktops) with redhat using the ATI Catalyst Control Center.
As in your post, you have ATI cards, so go to the ATI Driver Download page, and download your driver.
Usually, just with a single reboot after successfully installing the drivers, it should detect the two screens...

adamk75 08-08-2011 04:49 AM

Quote:

Originally Posted by paulmarc (Post 4436621)
I was able to have dual screens (with spanning desktops) with redhat using the ATI Catalyst Control Center.
As in your post, you have ATI cards, so go to the ATI Driver Download page, and download your driver.
Usually, just with a single reboot after successfully installing the drivers, it should detect the two screens...

This is bad advice. If you look at the OPs posts, you'll see that the video card in question is a Radeon 7000, which has never been supported by the proprietary drivers from AMD/ATI.

Adam

paulmarc 08-08-2011 05:07 AM

One could try the ATI open source drivers:
http://cgit.freedesktop.org/xorg/dri...video-radeonhd
http://cgit.freedesktop.org/xorg/driver/xf86-video-ati
I hope this helps...

adamk75 08-08-2011 05:27 AM

radeonhd is also for much newer video cards. xf86-video-ati should be used by default for that video card on any distribution from the last 10 years.

Perhaps, before recommending someone install different drivers, we try to figure out what's wrong with their current setup?

Adam

rmhandlinux 08-08-2011 04:29 PM

Monitors - the status
 
Hi Paul, Tink, ...,
I abandoned the second monitor as a distraction. Then 'xrandr' showed a list of resolutions, (one *'ed) and something, now lost.

Now reconnected, and xrandr says:- Xlib: extension "RANDR" missing on display ":0.0" Rather different.

Correction/additions to previous input:
The video cards are one, dual-head Radeon 7000/VE (not two cards)
I have two Sharp monitors: a LL-T19D1-B and a LL=191A-B. No Sharp monitors are listed in the cofiguration screen, so I called out generic LCD at 1024x768.

Thanks all of you.

adamk75 08-08-2011 04:42 PM

Please show us your /var/log/Xorg.0.log file.

Adam

rmhandlinux 08-08-2011 05:31 PM

Log file
 
I'm on my Windows machine, and I don't know how to get a file from the Linux box to here. I have looked briefly at the file (it is very long), and I did notice 'Failed to detect second monitor'. I'll work on getting the whole file across,

Dick


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