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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
  • 1,052
  • It seems to me to me you've switched from nouveau driver to nvidia binary driver. That could explain the slow switching... – solsTiCe Oct 30 '15 at 10:58
  • Is there a bug report for that? Note, that this seems to happen also for a colleague without Nvidia chip. – Alex Oct 30 '15 at 12:49
  • @solsTiCe I am not sure if I understand you correctly. Do you say the driver switch happens, when I switch from console/desktop or locker/desktop ? Or do you mean I switched drivers when dist-upgrading. – Alex Nov 04 '15 at 08:42
  • Please provide some more information about which graphics card you have and what kind of PC you use. – cl-netbox Nov 05 '15 at 10:09
  • @cl-netbox: I updated my question – Alex Nov 05 '15 at 14:39

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
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  • Did not help. Also be aware that a colleague has the same problem and is using an Intel Graphics Adapter. – Alex Nov 05 '15 at 15:47
  • @Alex : Maybe something went wrong during the upgrade process - a kernel upgrade (from 3.19 to 4.2) is not a trivial thing - you might consider to perform a clean installation of Ubuntu 15.10 and immediately after this follow the last part (drivers install) of my answer. This solution helped in several other cases ! :) – cl-netbox Nov 05 '15 at 15:57
  • My colleague did a clean install and has the same problem. – Alex Nov 05 '15 at 17:14
  • @Alex : Please try it on your own computer - every machine is different - so it is not helpful for you to compare it with your colleagues PC - especially when they have different graphics card solutions ! :) – cl-netbox Nov 05 '15 at 17:23
  • I am just thinking it might be a GPU independent problem... – Alex Nov 05 '15 at 19:43
  • Okay it looks like my colleague's PC seems to have a different problem. On this, the switch to console is instant. Did you base your answer on any specific bug ticket? Could you paste references? I am wondering if there is any way without a complete new installation to fix this. – Alex Nov 06 '15 at 13:38
  • Or is it maybe normal, that the screens take some time to adjust modes? In the locker I have a different ordering of the 3 screens than in my desktop. Maybe that is why it switches... – Alex Nov 06 '15 at 13:45
  • @Alex : Yes this might be possible ... graphics things are never trivial especially when using dedicated or switchable graphics solutions and combining several screens. So it is important to always have the very latest stable NVIDIA drivers installed. :) – cl-netbox Nov 06 '15 at 13:56
  • Anyways, it did not help. I am wondering if there is another way than reinstalling the system (which is also not proven to help) – Alex Nov 11 '15 at 13:38
  • @Alex : I would really give it a try - with these instructions I indeed could solve many similar problems ! :) – cl-netbox Nov 11 '15 at 13:45
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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
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