Getting a separate DISPLAY for each screen connected

Sat Aug 12 07:43:23 UTC 2017

On Sat, Aug 12, 2017 at 7:20 AM, Ben Hildred <42656e at gmail.com> wrote:

>
> On Fri, Aug 11, 2017 at 1:00 PM, Alex Deucher <alexdeucher at gmail.com>
> wrote:
>
>> On Fri, Aug 11, 2017 at 1:29 PM, Tor Rune Skoglund <trs at fourc.eu> wrote:
>> > 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 sounds like something have been working on.
>
>>
>> > This is pure X, no window manager.
>>
>
> This is not a pecom system by chance?
>

No, it our own Gentoo-based Linux distro.

> 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
>>
>> Not so quick, It is not quite so simple. Specifically it could be but
> probably is not in an embedded application because behavior depends on the
> video card. Specifically on one test box equipped with two video cards
>  (one on the motherboard, one in a pcie slot) the first video card could
> not be configured to host multiple screens although it would gladly support
> multiple monitors. The other video card would work either as two screens
> driving two monitors, one screen driving two monitors or as part of a
> shared screen driving four monitors. From my testing on board cards are
> unlikely to support dual screen, addin cards are likely to support dual
> screen and one screen per video card always worked. The arch link is indeed
> a good place to start.
>

Alex and Ben, thanks for your suggestions. We will look into the arch link.

Actually, is it not "really" an embedded solution since it is running (in
this case) on a standard Lenovo M910q PC meant to be deployed in a kiosk
setup. The PC has two DP connectors and an additional HDMI. xorg detects 3
pipes. (The two DP connectors are connected to HDMI monitors using a
converter, so I guess that is why they show up as HDMI.)

Btw, I seem to remember back from my university days in the 90-ties that
the workstations at the uni by default did what we actually want back then,
i.e. dual monitor workstations came up with DISPLAYs :0.0 and :0.1. But
that's a long time ago!  :-)

>
>
>> >
>> > 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
>> >
>> >
>> >
>> > _______________________________________________
>> > xorg at lists.x.org: X.Org support
>> > Archives: http://lists.freedesktop.org/archives/xorg
>> > Info: https://lists.x.org/mailman/listinfo/xorg
>> > Your subscription address: %(user_address)s
>> _______________________________________________
>> xorg at lists.x.org: X.Org support
>> Archives: http://lists.freedesktop.org/archives/xorg
>> Info: https://lists.x.org/mailman/listinfo/xorg
>> Your subscription address: %(user_address)s
>
>
> --
> Ben Hildred
> Automation Support Services
>
>
BR,
Tor Rune Skoglund, trs at fourc.eu
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.x.org/archives/xorg/attachments/20170812/04b75cb3/attachment.html>