secondary screen only works until login

[Colin Law]

On 29 August 2017 at 20:53, Xen <list at xenhideout.nl> wrote:
> Dave Stevens schreef op 29-08-2017 20:57:
>>
>> Hi,
>>
>> I'm using 16.04 on a Toshiba laptop. I want to use a secondary display,
>> a Samsung SyncMaster 712n. I have it connected to the Toshiba's
>> external VGA port. The display powered up and showed system activity
>> right up until the automatic user login took place. I had the system
>> configured to log me in without asking for a password. When the login
>> took place the secondary display went blank. The system control panel
>> shows an unknown secondary display.
>>
>> In an attempt to see where the problem lies I made a new (second) user
>> with a password and required a credential check at login. When I log in
>> as the new user the secondary screen mirrors the main laptop screen and
>> continues to work until I logout then log back in as the previous
>> (admin) user, then it blanks.
>>
>> I suppose if I knew more about the graphic setup this would tell me
>> where to look for more info but I don't.
>>
>> Anyone have a suggestion about where to look?
>
>
> Yes always just look at xrandr I guess.
>
> xrandr is a tool you can use to make those changes.

Note that for a second user the second display works correctly, so it
should not be necessary to do anything with xrandr, he needs to find
out what has got messed up for the original user.

Dave, when logged in as the second user what does System Settings >
Displays say about the display?

Colin