[SOLVED] Re: Changing monitor resolution on 12.04

Jim Byrnes jf_byrnes at comcast.net
Thu Dec 13 18:00:02 UTC 2012

On 12/13/2012 11:23 AM, Jim Byrnes wrote:
> On 12/13/2012 10:31 AM, Liam Proven wrote:
>> On 13 December 2012 16:23, Jim Byrnes <jf_byrnes at comcast.net> 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.
> Neither am I.  The same equipment was easy to setup and worked just fine
> under 10.04.
>> 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.
>> http://en.wikipedia.org/wiki/EDID
> My system has vga and dvi connections. The left hand monitor is an HP
> with a hdmi & vga connections. It is hooked up using a dvi to hdmi
> adapter and it is the monitor that is recognized at 1920x1080 resolution
> by the driver.  The right hand monitor is a Hannspree. It is hooked up
> vga to vga. It is the one that under 10.04 could achieve 1920x1080 but
> under 12.04 cannot.
> I did find one possible solution that involved EDID. I tried to follow
> along with what he was doing, but frankly the whole thing made my head
> hurt so I started to look for a simpler solution.  I'll to find it again
> and try to understand it this time
>> 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."
> Thanks for the info.  I seems to suggest that simply swapping xorg.conf
> files is not going to help but I guess I'll give it a try.
> Is there a way to revert back to the driver used in 10.04?
> Regards,  Jim

It was that simple.  Swapping in the xorg.conf from 10.04 worked.  After 
making the change I restarted.  When the system came back up it  popped 
up an error dialog saying something about unable to use stored 
configurations, BUT I had 1920x1080 on both monitors. I re-booted again 
so I could write down the exact error message wording, but on the 
re-boot there was no error message so I guess all is well.

Regards,  Jim

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