configure multiple display on ubuntu 11 with a display that does not identify itself

uzill · 01-20-2012, 07:15 PM

the problem:
my Dell u2711 has a problem with identifying itself on hdmi port (irrespective to OS, different computers).
VGA port works fine probably display and dvi should be fine as well!

Since the ubuntu cannot identify the monitor it sets 640x480 resolution when the monitor can handle 1920x1080 on hdmi!

system:
I have a dell XPS m1530(laptop) with nvidia 8600GT.
Laptop display resolution: 1680x1050 (seiko/epson make according to nvidia driver)
connected to Dell u2711 on HDMI.

Nvidia detects the Dell u2711 as "DFP-1" with max resolution "640x480"

Requesting solution:

one possible solution is fixing the monitor: Dell will replace the monitor with a refurb, but my monitor is in pristine condition with just the hdmi problem! And you will never know what Dell is going to send, might have annoying minor scratches on the screen
I managed to fix the problem on windows but not on ubuntu yet!

So, i request any help in fixing this problem! Thanks for your time!!

cheers.

EricTRA · 01-21-2012, 01:28 AM

Hello and welcome to LinuxQuestions,

Have you only tried using the NVidia tools? Did you check with for example xrandr what the capabilities of your output(s) are? With the monitor connected can you try the following and post the output:

Code:

xrandr --verbose

Looking forward to your participation in the forums. Have fun with Linux.

Kind regards,

Eric

uzill · 01-21-2012, 06:17 AM

Hi Eric,

Thanks for the quick reply!!

Yes i have pretty much just used Nvidia tool! And also bit of playing with xorg.conf--- with no success!

Here is the output from "xrandr --verbose" command (with the external monitor connected on HDMI)

Quote:

xrandr: Failed to get size of gamma for output default
Screen 0: minimum 1680 x 1050, current 2320 x 1050, maximum 2320 x 1050
default connected 2320x1050+0+0 (0x162) normal (normal) 0mm x 0mm
Identifier: 0x160
Timestamp: 471951725
Subpixel: unknown
Clones:
CRTC: 0
CRTCs: 0
Transform: 1.000000 0.000000 0.000000
0.000000 1.000000 0.000000
0.000000 0.000000 1.000000
filter:
1680x1050 (0x161) 88.2MHz
h: width 1680 start 0 end 0 total 1680 skew 0 clock 52.5KHz
v: height 1050 start 0 end 0 total 1050 clock 50.0Hz
2320x1050 (0x162) 124.2MHz *current
h: width 2320 start 0 end 0 total 2320 skew 0 clock 53.5KHz
v: height 1050 start 0 end 0 total 1050 clock 51.0Hz
2320x1050 (0x163) 121.8MHz
h: width 2320 start 0 end 0 total 2320 skew 0 clock 52.5KHz
v: height 1050 start 0 end 0 total 1050 clock 50.0Hz
1680x1050 (0x176) 91.7MHz
h: width 1680 start 0 end 0 total 1680 skew 0 clock 54.6KHz
v: height 1050 start 0 end 0 total 1050 clock 52.0Hz
2320x1050 (0x198) 126.7MHz
h: width 2320 start 0 end 0 total 2320 skew 0 clock 54.6KHz
v: height 1050 start 0 end 0 total 1050 clock 52.0Hz

connections on the laptop:
*VGA (max resolution:2048x1536 )
*HDMI (max resolution: 1920x1050 )

connections on the monitor

*VGA (max resolution:2048x1536 )
*HDMI (max resolution: 1920x1050 )
*Display port
*two DVI port

monitor can support 2560 x 1440 on DVI (have tried with a mac book but my laptop does not have DVI and i think the graphics card does not support)

Approximately a year ago it was working fine! When i connect the monitor on HDMI to the laptop on Ubuntu/Windows 7 they used to work perfectly! But I dont know what happened to the monitor the computer stopped recognising the details of the monitor! On ubuntu, it says DFP-1 (probably digital flat panel) and unknown display on windows.
The laptop works fine with my university monitor (HP 22in with DVI) on DVI-HDMI cable. So i guess its not the laptop! And also I checked the monitor on another laptop with HDMI with windows7, it did not detect!

I kinda need to tell the graphics driver that a dell U2711 is connected over HDMI and can support 1920x1050

Thanks again!!

Cheers,

Uzill

Samotnik · 01-21-2012, 07:15 AM

Umpf. People have absolutely forgotten about Xorg configurability. Ever heard about modelines?

RockDoctor · 01-23-2012, 01:10 PM

As root,

Code:

Xorg -configure :1

will generate the file /root/xorg.conf.new. You can add modelines as appropriate to the appropriate "Monitor" section, and resolutions to the appropriate "Display" subsections and "Screen" section. To get the modelines, use

Code:

gtf

gtf run without parameters, it will illustrate the proper usage. Once you've edited /root/xorg.conf.new to include the required informatio, copy it to /etc/X11/org.conf and restart X