Changing monitor resolution on 12.04

Liam Proven lproven at
Thu Dec 13 16:31:23 UTC 2012

On 13 December 2012 16:23, Jim Byrnes <jf_byrnes at> wrote:
> On 12/12/2012 12:31 PM, James wrote:
> You seem to be on kde, I am on Unity/Gnome and don't seem to have a Xstartup
> file.
> This got me thinking.  I have a perfectly working twinview setup on 10.004.
> I just compared the two xorg.conf files. The 10.04 one has references to two
> monitors and screens and the 12.04 one refers to only one.  I wonder if it
> is as simple as copying the 10.04 xorg.conf to 12.04?  Probably not but I
> think I will give it a try later.

Just an FYI.

I recently installed 12.10 on my PC. New machine but with the nVidia
GeForce 230 from my old PC installed. I'm not a gamer but I use
dualhead; it may not be the fastest but it does all I need and more.

On 12.04 my setup - identical twin Dell D1626HT 21" CRTs - worked
fine, with both at 1600×1200 at 85Hz.

On 12.10 this was not possible. Much experimenting - including xrandr
- revealed that the nVidia driver would not permit me to set this res
on my right-hand screen.

The reason was that the LHS VDU was connected via a DVI-VGA adaptor
and VGA-VGA cable. The RHS one was on a DVI-VGA then a VGA-BNC cable
with separate R/G/B/v-sync/h-sync cables. This gives a better picture.

The thing is, a BNC cable does not transmit monitor information back
to the PC - this is called EDID data.

Without it, the driver didn't know what screen I had and would not
allow anything over 800×600 at 60Hz - playing it very safe for almost
any monitor from this century.

It's not Ubuntu's fault (tho' Ubuntu's monitor selection tools are
pathetic.) It's the nVidia driver being overly cautious.

My workaround was to switch to a VGA-VGA cable.

I cannot suggest anything for you, but I am pointing at the nVidia
driver and saying "j'accuse."

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