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Since the upgrade to 15.10 I noticed that screen modes switches take around 5 seconds (the screen is black then)

  1. When switching from console to XFCE desktop via Ctrl+Alt+F1 / Ctrl+Alt+F7
  2. When locking the screen / unlocking

In the second case I was able to mitigate the effect a bit by using LightLocker, as these seems to not switch the modes anymore.

Happens for me on a Nvidia graphics card, but also for a colleague with Intel.

I am not sure if this happend before 15.10, because there I used LightLocker and might have not notices the problem.

Hardware Info:

  • Desktop PC
  • GPU: NVIDIA Corporation GK106 [GeForce GTX 650 Ti] (rev a1)
  • 3 Screens attached

Software:

  • Ubuntu 15.10
  • XFCE
  • NVIDIA binary driver version 352.41

Xorg.0.log during switching:

[ 21465.869] (II) NVIDIA(0): Setting mode "DVI-D-0: nvidia-auto-select @1920x1200 +1920+0 {ViewPortIn=1920x1200, ViewPortOut=1920x1200+0+0}, HDMI-0: nvidia-auto-select @1920x1200 +3840+0 {ViewPortIn=1920x1200, ViewPortOut=1920x1200+0+0}, DVI-D-1: nvidia-auto-select @1920x1200 +0+0 {ViewPortIn=1920x1200, ViewPortOut=1920x1200+0+0}"
[ 21466.010] (--) NVIDIA(GPU-0): CRT-0: disconnected
[ 21466.010] (--) NVIDIA(GPU-0): CRT-0: 400.0 MHz maximum pixel clock
[ 21466.010] (--) NVIDIA(GPU-0): 
[ 21466.016] (--) NVIDIA(GPU-0): DELL U2412M (DFP-0): connected
[ 21466.016] (--) NVIDIA(GPU-0): DELL U2412M (DFP-0): Internal TMDS
[ 21466.016] (--) NVIDIA(GPU-0): DELL U2412M (DFP-0): 330.0 MHz maximum pixel clock
[ 21466.016] (--) NVIDIA(GPU-0): 
[ 21466.022] (--) NVIDIA(GPU-0): DELL U2412M (DFP-1): connected
[ 21466.022] (--) NVIDIA(GPU-0): DELL U2412M (DFP-1): Internal TMDS
[ 21466.022] (--) NVIDIA(GPU-0): DELL U2412M (DFP-1): 165.0 MHz maximum pixel clock
[ 21466.022] (--) NVIDIA(GPU-0): 
[ 21466.045] (--) NVIDIA(GPU-0): DELL U2412M (DFP-2): connected
[ 21466.045] (--) NVIDIA(GPU-0): DELL U2412M (DFP-2): Internal TMDS
[ 21466.045] (--) NVIDIA(GPU-0): DELL U2412M (DFP-2): 330.0 MHz maximum pixel clock
[ 21466.045] (--) NVIDIA(GPU-0):
Alex
  • 1,062

2 Answers2

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To solve your problem install the latest current stable short-lived branch NVIDIA drivers 355.

First uninstall every NVIDIA related software you have had installed before.

Boot into Ubuntu and when the login screen appears press Ctrl+Alt+F1.

Enter your user name and password and then execute:

sudo apt-get purge nvidia*  
sudo reboot

If you had bumblebee installed remove the packages as well
(the switching capability will be replaced by nvidia-prime).

In this case the commands would be:

sudo apt-get purge nvidia* bumblebee  
sudo reboot

Now install the new drivers and NVIDIA Optimus support from the Proprietary GPU drivers PPA.

When the login screen appears press Ctrl + Alt + F1.

Enter your user name and password and then execute:

sudo add-apt-repository ppa:graphics-drivers/ppa
sudo apt-get update
sudo apt-get install nvidia-355 nvidia-prime
sudo reboot

In case you have to adjust which card to use in BIOS select NVIDIA or switchable graphics mode.

Open NVIDIA X Server Settings -> Prime Profiles to switch between the intel and NVIDIA GPUs.

cl-netbox
  • 31,491
0

I solved this in a different way.

I always locked the screen via Ctrl+Alt+Entf which was set in system shortcuts to gnome-screensaver-command and blanked the screen + obviously switched the mode.

When I use xflock4 for locking, the screensaver starts and unlocking works fast - without any screen mode switching.

Alex
  • 1,062