Getting a separate DISPLAY for each screen connected

[Alex Deucher]

On Fri, Aug 11, 2017 at 1:29 PM, Tor Rune Skoglund <trs at fourc.eu> wrote:
> Dear List,
>
> Been digging a lot to try to find a good solution for my problem here:
>
> We are using xorg for an "embedded" system, on which we would like to get a
> separate DISPLAY setting for each of the computer's gfx connectors. As it is
> today, by default HDMI1, HDMI2 and HDMI3 are cloned, By using xrandr and the
> left-of and right-of options on the connectors, we are able to extend the
> size to span across all the monitor connectors, and the total size of Screen
> 0 gets adjusted automatically. (Actually quite impressed by this!)
>
> However, this is actually not really what we want. We would like each HDMIx
> to be a separate display, i.e. HDMI1 should be :0.0, HDMI2 should be :0.1
> and HDMI3 should be :0.2 .
>
> This is pure X, no window manager.
>
> I guess this is a simple config option somewhere.... I will be very grateful
> if someone could point me in the right direction. :)

Google for zaphod or xinerama configuration.  If you read a xinerama
howto, the configuration is the same, just don't enable the xinerama
extension.  See here for a sample config:
https://wiki.archlinux.org/index.php/multihead#Xinerama

Alex

>
> System info:
>
> Intel Kaby Lake chipset: Driver loaded during kernel boot:
> # dmesg | grep i915
> [    0.947501] [drm] Finished loading i915/kbl_dmc_ver1_01.bin (v1.1)
> Gentoo - kernel 4.9.41
> xorg-server verison 1.19.3
> mesa version 17.0.6
> No xorg.conf (everything autodetected)
> No errors or (relevant) warnings i /var/log/Xorg.0.log. (Except missing
> fonts warnings)
> Outputs are assigned during xinit:
> [   476.723] (--) intel(0): Output HDMI1 using initial mode 1600x1200 on
> pipe 0
> [   476.723] (--) intel(0): Output HDMI2 using initial mode 1280x1024 on
> pipe 1
> [   476.723] (--) intel(0): Output HDMI3 using initial mode 1680x1050 on
> pipe 2
> xrandr --query:
>
> # DISPLAY=:0 xrandr --query
> Screen 0: minimum 8 x 8, current 4560 x 1200, maximum 32767 x 32767
> DP1 disconnected (normal left inverted right x axis y axis)
> DP2 disconnected (normal left inverted right x axis y axis)
> DP3 disconnected (normal left inverted right x axis y axis)
> HDMI1 connected 1600x1200+1280+0 (normal left inverted right x axis y axis)
> 410mm x 310mm
>    1600x1200     60.00*+
>    1280x1024     60.02
>    1280x960      60.00
>    1024x768      60.00
>    800x600       60.32
>    640x480       59.94
>    720x400       70.08
> HDMI2 connected primary 1280x1024+0+0 (normal left inverted right x axis y
> axis) 380mm x 300mm
>    1280x1024     60.02*+  75.02
>    1152x864      75.00
>    1024x768      75.03    60.00
>    800x600       75.00    60.32
>    640x480       75.00    59.94
>    720x400       70.08
> HDMI3 connected 1680x1050+2880+0 (normal left inverted right x axis y axis)
> 470mm x 300mm
>    1680x1050     59.95*+
>    1280x1024     75.02    60.02
>    1152x864      75.00
>    1024x768      75.03    60.00
>    800x600       75.00    60.32
>    640x480       75.00    59.94
>    720x400       70.08
> VIRTUAL1 disconnected (normal left inverted right x axis y axis)
>
> Best regards,
> Tor Rune Skoglund, trs at fourc.eu
>
>
>
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