Solved DisplayPort daisy chaining

JohnnySorocil

JohnnySorocil

Does anyone has successfully connected multiple monitors via single DisplayPort cable?

I am trying with FreeBSD 12.1-RELEASE on ThinkPad T430s and monitors are connected:
T430s -> miniDP to DP adapter -> Dell U2419HC -> Dell U2419H.
MST is enabled on first monitor and that setup worked on Windows 10 on another PC (although with much newer hardware).
Currently xrandr only shows first monitor and picture is duplicated on both monitors:
Code: 
Screen 0: minimum 320 x 200, current 1920 x 1080, maximum 8192 x 8192
LVDS1 connected primary (normal left inverted right x axis y axis)
   1920x1080     60.00 +  59.96    59.93  
   1680x1050     59.95    59.88  
   1400x1050     59.98  
   1600x900      59.95    59.82  
   1280x1024     60.02  
   1400x900      59.96    59.88  
   1280x960      60.00  
   1368x768      59.88    59.85  
   1280x800      59.81    59.91  
   1280x720      59.86    59.74  
   1024x768      60.00  
   1024x576      59.90    59.82  
   960x540       59.63    59.82  
   800x600       60.32    56.25  
   864x486       59.92    59.57  
   640x480       59.94  
   720x405       59.51    58.99  
   640x360       59.84    59.32  
VGA1 disconnected (normal left inverted right x axis y axis)
HDMI1 disconnected (normal left inverted right x axis y axis)
DP1 connected 1920x1080+0+0 (normal left inverted right x axis y axis) 527mm x 296mm
   1920x1080     60.00*+  50.00    59.94  
   1920x1080i    60.00    50.00    59.94  
   1600x900      60.00  
   1280x1024     75.02    60.02  
   1152x864      75.00  
   1280x720      60.00    50.00    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  
HDMI2 disconnected (normal left inverted right x axis y axis)
HDMI3 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)

CPU & GPU are:
Code: 
CPU: Intel(R) Core(TM) i7-3520M CPU @ 2.90GHz (2893.49-MHz K8-class CPU)
Intel HD Graphics 4000 (integrated Ivy Bridge GPU)

Packages:
Code: 
xorg-server-1.20.8_1,1
mesa-dri-19.0.8
drm-fbsd12.0-kmod-4.16.g20200221
drm-kmod-g20190710

Xorg log attached
 

Attachments

  • Xorg.0.log.txt
    48.7 KB · Views: 117
According to this Intel HD 4000 GPU doesn't support DisplayPort 1.2 (minimal version which has MST). ThinkPad T440p has support and MST is working as expected.
 
Yes, I can also connect one monitor to T430s via mini DP -> HDMI or mini DP -> DP, but not both monitor with single mini DP output (daisychained, like with newer T440 with DisplayPort 1.2).
Another possibility is to connect both monitors to dock or use VGA -> HDMI adapter for 2nd monitor.
 
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