Changing monitor resolution on 12.04

[Liam Proven]

On 13 December 2012 17:23, Jim Byrnes <jf_byrnes at comcast.net> 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.

Yes, I know, you said.

>> 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.

Yes, I know, you've told me/us before. :¬)

> 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

Might be worth a bash.

>> 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.

This may help but I doubt it:
http://liam-on-linux.livejournal.com/20637.html

> Is there a way to revert back to the driver used in 10.04?

Not AFAIK. Others may know better.

-- 
Liam Proven • Profile: http://lproven.livejournal.com/profile
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