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#1 2017-07-26 13:52:33

Arzigogolato
Member
Registered: 2017-02-02
Posts: 3

Random xrandr behaviour with external monitor

Hello,
   I need some help with the configuration of my laptop. It has a 4K display and I'm using it with external monitors. I followed the excellent guide on the wiki and I have now two simple scripts which configure it quickly when I'm using different external monitors (work/home/etc...).

Everything is working like a charm...sometimes...what I mean is that right now it is working perfectly but sometimes the mood of my laptop changes. This is the current output of xrandr:

Screen 0: minimum 320 x 200, current 7680 x 2160, maximum 8192 x 8192
eDP-1 connected primary 3840x2160+3840+0 (normal left inverted right x axis y axis) 344mm x 194mm
   3840x2160     59.98*+
   2048x1536     60.00  
   1920x1440     60.00  
   1856x1392     60.01  
   1792x1344     60.01  
   1600x1200     60.00  
   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  
DP-1 disconnected (normal left inverted right x axis y axis)
HDMI-1 connected 3840x2160+0+0 (normal left inverted right x axis y axis) 598mm x 336mm
   1920x1080     60.00*+  50.00    59.94  
   1680x1050     59.88  
   1600x900      60.00  
   1280x1024     60.02  
   1440x900      59.90  
   1280x800      59.91  
   1280x720      60.00    50.00    59.94  
   1024x768      70.07    60.00  
   800x600       72.19    60.32    56.25  
   720x576       50.00  
   720x480       60.00    59.94  
   640x480       72.81    66.67    60.00    59.94  
   720x400       70.08  
DP-2 disconnected (normal left inverted right x axis y axis)

And this is the code I'm using when I connect the external monitor:

xrandr --output HDMI-1 --mode 1920x1080 --scale 2x2 --pos 0x0 --rotate normal --output DP-1 --off --output eDP-1 --primary --mode 3840x2160 --pos 3840x0 --rotate normal --output DP-2 --off

What is random is that, sometimes (as it was before rebooting), the two screens are named XWAYLAND1 and XWAYLAND2 (the output of xrandr is very short, including only one configuration) . Not only the previous command doesn't work, but trying to scale XWAYLAND2 doesn't do anything but trowing an error at bash. So far, the only solution I found to get a decent scaling is rebooting and hoping the next time xrandr configuration will be as above.

At the beginning I thought it was a problem happening when connecting HDMI after the computer booted, but I'm not so sure of that anymore.

As soon as the problem will appear again I shall post the output of xrandr. In the meanwhile I was wondering if there are some more useful commands I could run in such eventuality, to understand better what does change, or if it is a known bug: I'm running gnome. Also the laptop is using bumblebee with propietary nvidia drivers and intel drivers because it has an Nvidia card and an intel one.

Thank you very much in advance!
Best,
Arzigogolato

Last edited by Arzigogolato (2017-07-26 13:53:13)


Sorry for my English: so far I've never touched the soil of an English speaking country...

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#2 2017-07-26 16:12:19

seth
Member
Registered: 2012-09-03
Posts: 49,981

Re: Random xrandr behaviour with external monitor

This depends on the kind of session you log into.
Gnome on Xorg will present you the above, but Gnome on wayland runs on (surprise) wayland and xrandr will run on xwayland - an emulation layer / nested X11 server that does no have actual output control.

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#3 2017-07-27 09:22:41

Arzigogolato
Member
Registered: 2017-02-02
Posts: 3

Re: Random xrandr behaviour with external monitor

Here's the output when things don't work (I'm at work but the errors are the same, give or take), but Seth, thanks, you already explained say wayland doesn't have output control.

$ xrandr
Screen 0: minimum 320 x 200, current 5760 x 2160, maximum 8192 x 8192
XWAYLAND0 connected 3840x2160+1920+0 (normal left inverted right x axis y axis) 340mm x 190mm
   3840x2160     59.96*+
XWAYLAND1 connected 1920x1080+0+0 (normal left inverted right x axis y axis) 480mm x 270mm
   1920x1080     59.88*+

$ xrandr --output XWAYLAND1 --mode 1920x1080 --scale 2x2 --pos 0x0 --rotate normal --output XWAYLAND0 --primary --mode 3840x2160 --pos 3840x0 --rotate normal
xrandr: Configure crtc 0 failed
X Error of failed request:  BadValue (integer parameter out of range for operation)
  Major opcode of failed request:  140 (RANDR)
  Minor opcode of failed request:  26 (RRSetCrtcTransform)
  Value in failed request:  0x27d
  Serial number of failed request:  33
  Current serial number in output stream:  34

Thank you Seth! Now I can see the problem is I don't know how/why sometimes gnome runs on xorg, sometimes on wayland (this is a noob question, I know...): the way I "log in" is always the same. I'll try to see why gnome sometimes opens up in one way, sometimes in the other, thanks!


Sorry for my English: so far I've never touched the soil of an English speaking country...

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#4 2017-07-27 09:54:09

seth
Member
Registered: 2012-09-03
Posts: 49,981

Re: Random xrandr behaviour with external monitor

gnome defaults to wayland - you've to explicitly select "gnome on xorg" if you want that.
If however you end up using the nvidia chip, wayland is (yet) not supported/defaulted and you'll run on xorg.
also check the wiki on gdm if you seek to avoid wayland

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