[GTALUG] Kernel and/or X upgrade broke my video setup

Scott Sullivan scott at ss.org
Wed Oct 11 10:01:07 EDT 2017


On 11/10/17 09:10 AM, ac via talk wrote:
> Hi Evan :)
> 
> i did not bite as I am not that knowledgable on kde...  but as nobody
> is saying anything maybe try:
> mv /home/scott/.config /home/scott/oldconfig
> 
> let us know?

That's a very broad approach with the disadvantage of moving settings 
for a whole lot of unrelated applications.

> Evan Leibovitch via talk <talk at gtalug.org> wrote:
>>
>> What's stranger (to me) is that when logged out (running LightDM) the
>> system DOES recognize my mouse pointer going from one screen to the
>> next. So somewhere it IS being recognized as a separate screen, but
>> once I log in that goes away and I'm back to a mirroring situation..

xrandr is command line too for handling multi-monitor arrangements. 
Desktop implement UIs that talk to this functionality, and handle the 
'memory' of layouts. KDE's for example will remember transient moinitor 
configureations, like my two different laptop docks at home and work, 
and will restore the right layout for each, matching against the Vendor 
IDs of the monitors.

The X Rotation and Reflection extensions are how multi-monitor modes are 
handled. In current times, functionally X has one giant display buffer, 
and monitors are small cutouts of that, arranged relative to each other.

This is the output of my currently 'mirrored' two outputs.

scott  ~  xrandr
Screen 0: minimum 320 x 200, current 1920 x 1080, maximum 8192 x 8192
eDP-1 connected primary 1920x1080+0+0 (normal left inverted right x axis 
y axis) 256mm x 144mm
    1920x1080     59.99*+
    1400x1050     59.98
    1280x1024     60.02
    1280x960      60.00
    1024x768      60.04    60.00
    960x720       60.00
    928x696       60.05
    896x672       60.01
    800x600       60.00    60.32    56.25
    700x525       59.98
    640x512       60.02
    640x480       60.00    59.94
    512x384       60.00
    400x300       60.32    56.34
    320x240       60.05
HDMI-1 disconnected (normal left inverted right x axis y axis)
HDMI-2 connected 1920x1080+0+0 (normal left inverted right x axis y 
axis) 477mm x 268mm
    1920x1080     60.00*+  59.94
    1680x1050     59.88
    1400x1050     59.95
    1600x900      60.00
    1280x1024     75.02    60.02
    1440x900      59.90
    1280x800      59.91
    1152x864      75.00
    1280x720      60.00    59.94
    1024x768      75.03    60.00
    800x600       75.00    60.32
    720x576       50.00
    720x480       60.00    59.94
    640x480       75.00    60.00    59.94
    720x400       70.08


It shows the available outputs, and any that have monitor detected, will 
have their supported Resolutions and refresh rates shown. The '+' is the 
recommended resolution reported by the hardware, and the
*' is the currently operating resolution and refresh rate.

An example invocation. Which turns off all but my laptops primary 
display. Note the missing '*' in the HDMI-2 resolution section.

xrandr --output eDP1 --auto --primary --rotate normal --output HDMI-1 
--off --output HDMI-2 --off

  scott  ~  xrandr
Screen 0: minimum 320 x 200, current 1920 x 1080, maximum 8192 x 8192 

eDP-1 connected 1920x1080+0+0 (normal left inverted right x axis y axis) 
256mm x 144mm
    1920x1080     59.99*+ 

    1400x1050     59.98 

    1280x1024     60.02 

    1280x960      60.00 

    1024x768      60.04    60.00 

    960x720       60.00 

    928x696       60.05 

    896x672       60.01 

    800x600       60.00    60.32    56.25 

    700x525       59.98 

    640x512       60.02 

    640x480       60.00    59.94 

    512x384       60.00 

    400x300       60.32    56.34 

    320x240       60.05
HDMI-1 disconnected (normal left inverted right x axis y axis)
HDMI-2 connected (normal left inverted right x axis y axis)
    1920x1080     60.00 +  59.94
    1680x1050     59.88
    1400x1050     59.95
    1600x900      60.00
    1280x1024     75.02    60.02
    1440x900      59.90
    1280x800      59.91
    1152x864      75.00
    1280x720      60.00    59.94
    1024x768      75.03    60.00
    800x600       75.00    60.32
    720x576       50.00
    720x480       60.00    59.94
    640x480       75.00    60.00    59.94
    720x400       70.08


I'm not familiar with what GUI application LightDM to manipulate xrandr, 
but with some research you can figure that out, and set your preferred.

I had to do a lot of work with this stuff when I worked at the VFX 
studio. Let's just say there were some painful combinations of hardware, 
binary Nvidia drives and artists insisting on Vertical monitors.

-- 
Scott Sullivan


More information about the talk mailing list