DP daisy chain with two Dell monitors and GTX 980M issues

Hi,

I’m on 358.09 - on a 4.3.0 kernel. My card is a GeForce GTX 980M – on an MSI laptop – and I am connected via the DP to two Dell U2415 monitors that are daisy chained. The first one running on DP 1.2 and the second on DP 1.1 – it’s required by Dell to make the daisy chaining work.

My pickle is the following: is I set up the three monitors as three separate screens – and enable Xinerama - everything works fine; the three monitors all work and I am an happy camper. Of course using Xinerama doesn’t play well with tons of things - not least the fact that it disables xrandr and makes Gnome – and other DM – cry and crash.

If I disable xinerama all in a sudden all sorts of things break loose – screens start dropping out and going into power saving mode and I am a very unhappy camper.

The closest that I have come to a solution is this configuration:

Section "ServerLayout"
    Identifier     "Layout0"
    Screen      0  "Screen0" 0 0
    InputDevice    "Keyboard0" "CoreKeyboard"
    InputDevice    "Mouse0" "CorePointer"
    Option         "Xinerama" "0"
EndSection

Section "Files"
EndSection

--- Input Devices Omitted ---

Section "Monitor"

    # HorizSync source: edid, VertRefresh source: edid
    Identifier     "Monitor0"
    VendorName     "Unknown"
    ModelName      "DELL U2415"
    HorizSync       30.0 - 83.0
    VertRefresh     49.0 - 61.0
    Option         "DPMS"
EndSection

Section "Monitor"

    # HorizSync source: edid, VertRefresh source: edid
    Identifier     "Monitor1"
    VendorName     "Unknown"
    ModelName      "DELL U2415"
    HorizSync       30.0 - 83.0
    VertRefresh     49.0 - 61.0
    Option         "DPMS"
EndSection

Section "Monitor"

    # HorizSync source: edid, VertRefresh source: edid
    Identifier     "Monitor2"
    VendorName     "Unknown"
    ModelName      "DELL U2415"
    HorizSync       30.0 - 83.0
    VertRefresh     49.0 - 61.0
    Option         "DPMS"
EndSection

Section "Device"
    Identifier     "Device0"
    Driver         "nvidia"
    VendorName     "NVIDIA Corporation"
    BoardName      "GeForce GTX 980M"
    Option         "ConnectedMonitor" "DP-0"
    Option         "CustomEDID" "DP-0:/etc/X11/panel_edid.bin"
    Option         "IgnoreEDID" "false"
    Option         "UseEDID" "true"
EndSection

Section "Device"
    Identifier     "Device1"
    Driver         "nvidia"
    VendorName     "NVIDIA Corporation"
    BoardName      "GeForce GTX 980M"
    Option         "ConnectedMonitor" "DP-3.8"
    Option         "CustomEDID" "DP-3.8:/etc/X11/dell_edid_1.2.bin"
    Option         "IgnoreEDID" "false"
    Option         "UseEDID" "true"
    BusID          "PCI:1:0:0"
EndSection

Section "Device"
    Identifier     "Device2"
    Driver         "nvidia"
    VendorName     "NVIDIA Corporation"
    BoardName      "GeForce GTX 980M"
    Option         "ConnectedMonitor" "DP-3.1"
    Option         "CustomEDID" "DP-3.1:/etc/X11/dell_edid_1.1.bin"
    Option         "IgnoreEDID" "false"
    Option         "UseEDID" "true"
    BusID          "PCI:1:0:0"
EndSection

Section "Screen"
    Identifier     "Screen0"
    Device         "Device0"
    Monitor        "Monitor0"
    DefaultDepth    24
    Option         "TwinView" "1"
    Option         "TwinViewXineramaInfoOrder" "DP-0"
    Option         "Stereo" "0"
    Option         "nvidiaXineramaInfoOrder" "DFP-1"
    Option         "metamodes" "DP-3.1: 1920x1200_60 +0+0, DP-3.8: 1920x1200_60 +1920+0, DP-0: 1920x1080_75 +3840+0"
    Option         "SLI" "Off"
    Option         "MultiGPU" "Off"
    Option         "BaseMosaic" "off"
    SubSection     "Display"
        Depth       24
    EndSubSection
EndSection

With this configuration the XServer comes up - with the DP 1.1 Monitor and the Laptop screen on, but the display in the middle (The first in the daisy chain and the one running DP 1.2) is off.

I created a small launcher on my desktop that simply does:

xset dpms force off

with that all of the screens go off - and then they all - including the center one - come back up and running. The idea came to me from reading this: http://ubuntuforums.org/showthread.php?t=2301503
This will work fine until I suspend or the screens are switched off due to inactivity, then there is a kind of lottery and one of the two Dells will come back to life and the other will stay black – until I reboot.

In all this it seems that xrandr -q still sees all of the screens as follows:

Screen 0: minimum 8 x 8, current 5760 x 1200, maximum 16384 x 16384
DP-3.8 connected 1920x1200+1920+0 (normal left inverted right x axis y axis) 518mm x 324mm
   1920x1200     59.95*+  59.88  
   1920x1080     60.00    59.94    50.00    29.97    25.00    23.97    60.05    60.00    50.04  
   1600x1200     60.00  
   1280x1024     75.02    60.02  
   1280x720      60.00    59.94    50.00  
   1152x864      75.00  
   1024x768      75.03    60.00  
   800x600       75.00    60.32  
   720x576       50.00    50.08  
   720x480       59.94    60.05  
   640x480       75.00    59.94    59.93  
DP-3.1 connected 1920x1200+0+0 (normal left inverted right x axis y axis) 518mm x 324mm
   1920x1200     59.95*+  59.88  
   1920x1080     60.00    59.94    50.00    29.97    25.00    23.97    60.05    60.00    50.04  
   1600x1200     60.00  
   1280x1024     75.02    60.02  
   1280x720      60.00    59.94    50.00  
   1152x864      75.00  
   1024x768      75.03    60.00  
   800x600       75.00    60.32  
   720x576       50.00    50.08  
   720x480       59.94    60.05  
   640x480       75.00    59.94    59.93  
HDMI-0 disconnected (normal left inverted right x axis y axis)
DP-0 connected primary 1920x1080+3840+0 (normal left inverted right x axis y axis) 382mm x 215mm
   1920x1080     75.00*+
DP-1 disconnected (normal left inverted right x axis y axis)
DP-2 disconnected (normal left inverted right x axis y axis)
DP-3 disconnected (normal left inverted right x axis y axis)
DP-4 disconnected (normal left inverted right x axis y axis)

But no xset, n xrandr -off and then on will make the dead screen come back to life.

I have tried all different releases of the NVidia drivers, but it seems that I can’t get no joy out of this configuration.

Is there something wrong in my configuration? Mind you: I tried the configuration done directly by the NVidia settings panel - but I get exactly the same kind of behaviour. Is there something else I can try?

Fabio

Hello,

you are correct, this is a bug in the driver. I’m in the same situation (openSUSE 13.2 and openSUSE 42.1 and tried the newest driver).

This can be even faster hackfixed by executing:

xset dpms force off; xset dpms force on

And if you want something kinda permanent, you can add this lines to xinitrc file or to the Xsetup file of your login manager (beware that you may have to use the full path to the xset binary)

kind regards, Kira Backes

I have exact the same problem with a GTX 970 and two daisy-chained Dell Ultrasharp U2515H. The daisy-chained monitor won’t come out of power saving mode until DPMS is forced off and on.

Thanks for the tip Fabio and kib!

Sadly Nvidia driver team still did not answer to my support request, but they probably left for holiday vacation.

So let’s hope that someday this will be fixed and we will no longer have blank/black displays due to broken daisy-chain support. Btw the Windows driver from Nvidia work fine of course with the same card and monitors…

Same here with a GTX 970 and two U2415. Any news?

Why are we being ignored? The problem still exists in the latest driver 361.28.

I still have the same problem with drivers version 375.20 and two Dell U2415. Do someone have any news about this?