LinuxQuestions.org
Review your favorite Linux distribution.
Go Back   LinuxQuestions.org > Forums > Linux Forums > Linux - Hardware
User Name
Password
Linux - Hardware This forum is for Hardware issues.
Having trouble installing a piece of hardware? Want to know if that peripheral is compatible with Linux?

Notices

Reply
 
Search this Thread
Old 10-05-2011, 09:38 PM   #1
shva
Member
 
Registered: Feb 2009
Distribution: Fedora, Arch, Debian, Ubuntu
Posts: 56

Rep: Reputation: 15
Dual monitors: one screen is flickering/blank in Ubuntu 11.04


Hi everyone,

I set up dual monitors (a 1920x1080 DVI monitor and an old 1024x768 VGA monitor) for Ubuntu 11.04, but one of them is flickering or just blank. However, either of them works fine in a single-monitor configuration. The output of "xrandr -q" is as follows:


Code:
Screen 0: minimum 320 x 200, current 1920 x 1080, maximum 16384 x 16384
HDMI-0 disconnected (normal left inverted right x axis y axis)
DVI-0 connected 1920x1080+0+0 (normal left inverted right x axis y axis) 521mm x 293mm
   1920x1080      60.0*+
   1680x1050      60.0  
   1280x1024      75.0     60.0  
   1440x900       59.9  
   1152x864       75.0  
   1024x768       75.1     70.1     60.0  
   832x624        74.6  
   800x600        72.2     75.0     60.3     56.2  
   640x480        72.8     75.0     66.7     60.0  
   720x400        70.1  
VGA-0 connected 1024x768+0+0 (normal left inverted right x axis y axis) 0mm x 0mm
   1024x768       60.0* 
   800x600        60.3     56.2  
   848x480        60.0  
   640x480        59.9

And the video card is Radeon HD 6450. Could anyone please help? Thanks.
 
Old 10-05-2011, 11:10 PM   #2
fukawi1
Member
 
Registered: Apr 2009
Location: Melbourne
Distribution: Fedora & CentOS
Posts: 854

Rep: Reputation: 189Reputation: 189
Some cards need you to use certain channels at a time, ie: the DVI and VGA channels may be the same channel, just a different plug.
Thats a poor way of explaining it, but just because the card has 3 outputs (HDMI, DVI, VGA) doesnt necessarily mean all 3 can be used..
Does the 1080 screen connected to the DVI, have a HDMI port on it? perhaps swapping that to HDMI, and trying again, and/or swapping the VGA to DVI (with an adapter)??

I remember having to do that with a NVIDA card a while back, i have 2x19" and 1x24" working on a HD 5770, with xrandr and fedora, but honestly, it worked out of the box with a fedora install. So ive had very little to do with xrandr..

Are you running the latest drivers? perhaps try swapping from the packaged drivers, to the proprietary drivers?
 
Old 10-06-2011, 08:07 PM   #3
shva
Member
 
Registered: Feb 2009
Distribution: Fedora, Arch, Debian, Ubuntu
Posts: 56

Original Poster
Rep: Reputation: 15
Quote:
Originally Posted by fukawi1 View Post
Some cards need you to use certain channels at a time, ie: the DVI and VGA channels may be the same channel, just a different plug.
Thats a poor way of explaining it, but just because the card has 3 outputs (HDMI, DVI, VGA) doesnt necessarily mean all 3 can be used..
Does the 1080 screen connected to the DVI, have a HDMI port on it? perhaps swapping that to HDMI, and trying again, and/or swapping the VGA to DVI (with an adapter)??

I remember having to do that with a NVIDA card a while back, i have 2x19" and 1x24" working on a HD 5770, with xrandr and fedora, but honestly, it worked out of the box with a fedora install. So ive had very little to do with xrandr..

Are you running the latest drivers? perhaps try swapping from the packaged drivers, to the proprietary drivers?

I don't have any DVI to VGA or HDMI to VGA cable off my hands, so I may not be able to try that. I tried the proprietary ATI driver, but somehow it just contaminated my system and made things break. Were you saying for your nvidia card, multiple monitors attached to one single video card worked?
 
Old 10-07-2011, 03:24 AM   #4
fukawi1
Member
 
Registered: Apr 2009
Location: Melbourne
Distribution: Fedora & CentOS
Posts: 854

Rep: Reputation: 189Reputation: 189
Quote:
Originally Posted by shva View Post
Were you saying for your nvidia card, multiple monitors attached to one single video card worked?
Correct, in the case of the old nvidia card, was setup as follows

gpu0 (AGP) Geforce 6200 (i think) - 1 x 19" (vga), 1 x 19" (dvi)
gpu1 (PCI) Geforce 6200 (i think) - 1 x 24" (dvi), 1 x 42" plasma (vga)

This used to take some fiddling to get working, some distro's were easier than others.

in the case of my current Radeon HD 5770
gpu0 (PCIe) HD 5770 - 1 x 19" (DVI), 1 x 24" (HDMI), 1x 19" (DisplayPort, with active DP-DVI adapter)

This worked out of the box with Fedora 14/15.
 
Old 10-07-2011, 08:35 AM   #5
adamk75
Senior Member
 
Registered: May 2006
Posts: 3,091

Rep: Reputation: 396Reputation: 396Reputation: 396Reputation: 396
shva, HD6xxx support is relatively new in the kernel. A lot of fixes for those GPUs went into the 3.0.* kernel, so you might want to try something newer than the default kernel in Ubuntu 11.04.
 
Old 10-07-2011, 10:58 PM   #6
wabbalee
Member
 
Registered: Oct 2006
Location: brisbane - australia
Distribution: mepis, ubuntu, zenwalk
Posts: 334

Rep: Reputation: 38
Hi, uhm.. flickering? I do think, without looking up the specs of your vga card, it being a radeon and my personal experience with them is good, in fact I have set up three screens with an extra pci nvidia for the third screen and set them up as one large desktop. iow i can move from screen to screen with mouse, the task bar stays on the middle screen.

my suggestion would be to see if you are not accidentally sending a to high a refresh rate to these screens, try a conservative 60Hz on all screens, and make sure you are not giving it a too high a resolution as well.

hope this will help somewhat

kind regards
Ron
 
Old 10-07-2011, 11:39 PM   #7
fukawi1
Member
 
Registered: Apr 2009
Location: Melbourne
Distribution: Fedora & CentOS
Posts: 854

Rep: Reputation: 189Reputation: 189
wabbalee,
Quote:
Originally Posted by shva View Post
Hi everyone,
However, either of them works fine in a single-monitor configuration.
Code:
Screen 0: minimum 320 x 200, current 1920 x 1080, maximum 16384 x 16384
HDMI-0 disconnected (normal left inverted right x axis y axis)
DVI-0 connected 1920x1080+0+0 (normal left inverted right x axis y axis) 521mm x 293mm
   1920x1080      60.0*+

VGA-0 connected 1024x768+0+0 (normal left inverted right x axis y axis) 0mm x 0mm
   1024x768       60.0*
It sounds to me like adamk75, is on the money.

Perhaps try a few live cd's, id suggest FC15 (as it just worked, for me at least), pay attention to the kernel and driver versions, and see if you can copy the config and replicate on the ubuntu install.
 
  


Reply

Tags
display, ubuntu 11.04


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
Using dual monitors/dual heads displays a black screen (Fedora 6) ttnunam Linux - General 4 04-21-2007 12:50 AM
dual screen problems with certain monitors, works for others hedpe Linux - Desktop 4 03-28-2007 09:10 PM
Screen Flickering Running Ubuntu NautTboy Linux - Newbie 9 02-23-2007 05:55 PM
[SOLVED] Dual Monitors, Swapping screen 1 for screen 0 almcneill Linux - Hardware 2 11-30-2006 12:54 PM
using dual-screen / monitors zegenie Linux - General 9 10-02-2002 12:24 PM


All times are GMT -5. The time now is 04:40 PM.

Main Menu
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
identi.ca: @linuxquestions
Facebook: linuxquestions Google+: linuxquestions
Open Source Consulting | Domain Registration