# HELP: Dell U2412M Monitor comes up in 1024x768 mode SOLVED

## Moriah

I have 2 of these monitors.  The older one (1 month older) works fine, but the one I got today comes up in 1024x768 mode instead of 1920x1200 mode.  In windows-7 it comes up fine, but control panel > display > advanced says it is a non-plug-n-play monitor.  In the /var/log/Xorg/0/log file it shows no EDID info for this monitor.  It seems to me that this newer monitor probably has a slightly different chip in it than the older one does, and the EDID info I have is out of date.  The log says I have EDID version 1.3; I do not know if this is current or not.  I suspect not, as my kernel is 2.6.37-gentoo-r4, which is pretty old, but there have been no security updates that would make me go to a newer kernel, so I have left well enough alone.  What can I do to get this thing to work?  It is running with Intel video on a Lenovo w500 laptop with a 1920x1200 pixel laptop monitor, and works great with that.  It also works great with my other (older) Dell U2412M monitor, but with this monitor, it comes up in 1024x768 like it doesn't recognize the monitor's capabilities.  This is in framebuffer console mode at boot as well as in X11 mode.  Funny thing is that when I first plugged it in, I already had the laptop up and running with another 1920x1200 monitor, and I just moved the VGA cable, and it worked great, so its not the actual ability, but just a recognition problem.

Anybody know how to fix this thing?    :Question: 

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## gorkypl

What video driver are you using? Maybe you can try setting resolution via xrandr, like

```
xrandr --output DVI-0 --mode 1920x1200
```

(change DVI-0 to your actual output).

If it works, you can set PreferredMode in Monitor section of xorg.conf

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## Moriah

xrandr refused topermit anything higher than 1024x768 on the vga monitor VGA1.

I did some additional experimentation, and I discovered that even my old display that always used to work no longer works properly now.  I thinkthe problem occurs during boot-up, as before, I always got 1920x1200 resolution on teh console, and now I still get it if I only use the internal laptop display, but if the external vga monitor is plugged in, the it goes to 1024x768 instead.

Something obviously got botched diring a recent upgrade.  I have not booted my laptop until recently (after I got the new display), so it could have gotten messed up as long as 2 weeks ago.

Does anyone have any idea what might have changed regarding display resolutions in the past few weeks?

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## Moriah

What changed was the monitor cable.    :Embarassed: 

I was very tired of having my monitor cable stretched across my desk right where I would like to place papers, books, etc., so I got longer cable the other day.  Apparently, that was the problem.  When I put a short cable back in the circuit, it worked properly again.

How long can a vga cable be and still work properly?

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## gorkypl

1920x1200 is a very high resolution for analog VGA cable, so I'd focus on the cable quality - shielding, thick wires etc.

It may be more important than the length itself. 

I guess DVI/HDMI is not an option?

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## Moriah

I have been using vga at this resolution for years.  It appears to me that the problem is more related to EDID than to the fidelity of the cable.  How is this EDID information transmitted to the video interface from the monitor?  Over the same signal wires as the video itsefl, or over some other signal wire?

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## Jaglover

Workaround would be ignoring EDID read from the monitor, if you otherwise are happy with picture quality.

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## gorkypl

EDID is transferred via separate wires, but still cable quality counts.

http://en.wikipedia.org/wiki/VGA_connector

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## Moriah

Well, I went to my old cable, and all is working fine once again; therefore, I conclude that the longer cable does not support EDID.   :Sad: 

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