Display resolution issue on 12.04 with external display on laptop

[Liam Proven]

On 28 May 2012 19:12, Chris Green <cl at isbd.net> wrote:
> On Mon, May 28, 2012 at 06:13:44PM +0100, Liam Proven wrote:
>> On 28 May 2012 17:55, Chris Green <cl at isbd.net> wrote:
>> > On Mon, May 28, 2012 at 05:22:28PM +0100, Liam Proven wrote:
>> >> On 28 May 2012 11:50, Chris Green <cl at isbd.net> wrote:
>> >> > We have just upgraded my wife's Dell Vostro v13 laptop from
>> >> > 10.04 to 12.04, it all works OK except that it doesn't work so well with
>> >> > an external monitor as it used to.
>> >> >
>> >> > What happens now when an external monitor is plugged in is that the
>> >> > laptop screen runs at 1366x768 (as it should) but the external VGA
>> >> > screen runs at 1024x768 and only shows the LH portion of the full
>> >> > 1366x768 screen.
>> >> >
>> >> > It used to work fine on 10.04, when the external monitor was plugged in
>> >> > the internal screen was disable and the external one ran at its native
>> >> > resolution 1680 x 1050.  Now what happens is that the internal screen
>> >> > contnues to run at 1366x768 and the external one runs at 1024x768 and
>> >> > shows only the LH portion of the full screen.
>> >> >
>> >> >
>> >> > Any ideas for a workaround/fix to get the external monitor right?
>> >>
>> >> What settings do you have in the Displays control panel?
>> >>
>> > Sorry, I'm running xubuntu so maybe shouldn't be asking here.
>> >
>> > However you have taken me some way to a solution as I can now *manually*
>> > select the right resolution needed.  It used to 'just work' all by
>> > itself though.
>> >
>> > Thanks.
>>
>> Ah.
>>
>> You didn't mention that, but then, I've found that if I mention that
>> I'm using Mint 9 rather than Ubuntu 10.04, people generally won't
>> answer me. If I don't mention this fact, I get Ubuntu-related answers
>> that work fine. :¬/
>>
> Quite!  :-)   I was assuming (maybe correctly) that this is an
> underlying ubuntu core issue rather than an xubuntu one.

I am not sure at the moment, TBH. I've not got a clear picture from
what you've written of what is happening.

> The external monitor wasn't there in the display settings the first time
> I looked.  Now it's there one can (manually) select which display to use
> and set the resolution for it.

Aha! Right.

I find that if the display is not connected (& turned on) /before
*buntu is booted/ then X often will not detect it correctly, although
sometimes the BIOS keystroke to switch between internal & external
displays will still work.

> Previously (we upgraded from 10.04) it just worked with resolution set
> and display selected according to whether the external display was
> plugged in or not, no manual intervention required.

Ah right!

>> FWIW I found that under LXDE and XFCE, their display managers could
>> not get me a working dual-head desktop on my Thinkpad X31, something
>> GNOME and Unity did with ease.
>>
> Dual head would be great but not really necessary.

OIC. This is something of a deal-breaker for me; I am a heavy user of
dual-head and prefer 2 smaller monitors to one big one.

-- 
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