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#1 2018-12-13 09:29:06

albinou
Member
From: Paris, France
Registered: 2012-04-08
Posts: 2

Optimus PRIME (i915 + nouveau): black screen on VGA output

Hi all,

I have an old Dell Latitude E6430 with the following intel and nvidia GPUs:

00:02.0 VGA compatible controller: Intel Corporation 3rd Gen Core processor Graphics Controller (rev 09)
01:00.0 VGA compatible controller: NVIDIA Corporation GF108GLM [NVS 5200M] (rev a1)

I would like to use 2 screens (LVDS + VGA). LVDS + HDMI works fine but I can't make the VGA output work (black screen).

I already ran a lot of tests but I can't solve my issue. Any help would be very appreciated. Details are given below.
Thanks!

Hardware configuration

From what I can understand:

  • the intel GPU can use the LVDS and VGA outputs

  • the nvidia GPU can use the LVDS, VGA, HDMI, DP-1 and DP-2 outputs

Here are a few commands that confirms this:

albinou@laptop ~$ xrandr --listproviders
Provider 0: id: 0x9f cap: 0xb, Source Output, Sink Output, Sink Offload crtcs: 4 outputs: 3 associated providers: 1 name:Intel
Provider 1: id: 0x66 cap: 0x7, Source Output, Sink Output, Source Offload crtcs: 2 outputs: 5 associated providers: 1 name:nouveau
albinou@laptop ~$ sudo cat /sys/kernel/debug/vgaswitcheroo/switch
0:IGD:+:Pwr:0000:00:02.0
1:DIS: :DynOff:0000:01:00.0
albinou@laptop ~$ xrandr
Screen 0: minimum 8 x 8, current 3280 x 1050, maximum 32767 x 32767
LVDS1 connected primary 1600x900+0+0 (normal left inverted right x axis y axis) 310mm x 170mm
   1600x900      59.99*+  59.95    59.82    39.99  
   1400x900      59.96    59.88  
   1368x768      60.00    59.88    59.85  
   1280x800      59.81    59.91  
   1280x720      59.86    60.00    59.74  
   1024x768      60.00  
   1024x576      60.00    59.90    59.82  
   960x540       60.00    59.63    59.82  
   800x600       60.32    56.25  
   864x486       60.00    59.92    59.57  
   800x450       60.00  
   640x480       59.94  
   720x405       59.51    60.00    58.99  
   640x360       59.84    59.32    60.00  
VGA1 connected 1680x1050+1600+0 (normal left inverted right x axis y axis) 490mm x 320mm
   1680x1050     59.88*+
   1280x1024     75.02    60.02  
   1280x960      60.00  
   1152x864      75.00  
   1024x768      75.03    70.07    60.00  
   832x624       74.55  
   800x600       72.19    75.00    60.32    56.25  
   640x480       75.00    72.81    66.67    59.94  
   720x400       70.08  
VIRTUAL1 disconnected (normal left inverted right x axis y axis)
LVDS-1-2 disconnected (normal left inverted right x axis y axis)
DP-1-1 disconnected (normal left inverted right x axis y axis)
DP-1-2 disconnected (normal left inverted right x axis y axis)
HDMI-1-1 connected (normal left inverted right x axis y axis)
   1680x1050     59.88 +
   1280x1024     75.02    60.02  
   1280x960      60.00  
   1152x864      75.00  
   1024x768      75.03    70.07    60.00  
   832x624       74.55  
   800x600       72.19    75.00    60.32    56.25  
   640x480       75.00    72.81    66.67    59.94  
   720x400       70.08  
VGA-1-2 disconnected (normal left inverted right x axis y axis)
  1680x1050 (0x67) 119.000MHz +HSync -VSync
        h: width  1680 start 1728 end 1760 total 1840 skew    0 clock  64.67KHz
        v: height 1050 start 1053 end 1059 total 1080           clock  59.88Hz
  1280x1024 (0x68) 135.000MHz +HSync +VSync
        h: width  1280 start 1296 end 1440 total 1688 skew    0 clock  79.98KHz
        v: height 1024 start 1025 end 1028 total 1066           clock  75.02Hz
  1280x1024 (0x69) 108.000MHz +HSync +VSync
        h: width  1280 start 1328 end 1440 total 1688 skew    0 clock  63.98KHz
        v: height 1024 start 1025 end 1028 total 1066           clock  60.02Hz
  1280x960 (0x6a) 108.000MHz +HSync +VSync
        h: width  1280 start 1376 end 1488 total 1800 skew    0 clock  60.00KHz
        v: height  960 start  961 end  964 total 1000           clock  60.00Hz
  1152x864 (0x6b) 108.000MHz +HSync +VSync
        h: width  1152 start 1216 end 1344 total 1600 skew    0 clock  67.50KHz
        v: height  864 start  865 end  868 total  900           clock  75.00Hz
  1024x768 (0x6c) 78.750MHz +HSync +VSync
        h: width  1024 start 1040 end 1136 total 1312 skew    0 clock  60.02KHz
        v: height  768 start  769 end  772 total  800           clock  75.03Hz
  1024x768 (0x6d) 75.000MHz -HSync -VSync
        h: width  1024 start 1048 end 1184 total 1328 skew    0 clock  56.48KHz
        v: height  768 start  771 end  777 total  806           clock  70.07Hz
  1024x768 (0x6e) 65.000MHz -HSync -VSync
        h: width  1024 start 1048 end 1184 total 1344 skew    0 clock  48.36KHz
        v: height  768 start  771 end  777 total  806           clock  60.00Hz
  832x624 (0x6f) 57.284MHz -HSync -VSync
        h: width   832 start  864 end  928 total 1152 skew    0 clock  49.73KHz
        v: height  624 start  625 end  628 total  667           clock  74.55Hz
  800x600 (0x70) 50.000MHz +HSync +VSync
        h: width   800 start  856 end  976 total 1040 skew    0 clock  48.08KHz
        v: height  600 start  637 end  643 total  666           clock  72.19Hz
  800x600 (0x71) 49.500MHz +HSync +VSync
        h: width   800 start  816 end  896 total 1056 skew    0 clock  46.88KHz
        v: height  600 start  601 end  604 total  625           clock  75.00Hz
  800x600 (0x72) 40.000MHz +HSync +VSync
        h: width   800 start  840 end  968 total 1056 skew    0 clock  37.88KHz
        v: height  600 start  601 end  605 total  628           clock  60.32Hz
  800x600 (0x73) 36.000MHz +HSync +VSync
        h: width   800 start  824 end  896 total 1024 skew    0 clock  35.16KHz
        v: height  600 start  601 end  603 total  625           clock  56.25Hz
  640x480 (0x74) 31.500MHz -HSync -VSync
        h: width   640 start  656 end  720 total  840 skew    0 clock  37.50KHz
        v: height  480 start  481 end  484 total  500           clock  75.00Hz
  640x480 (0x75) 31.500MHz -HSync -VSync
        h: width   640 start  664 end  704 total  832 skew    0 clock  37.86KHz
        v: height  480 start  489 end  492 total  520           clock  72.81Hz
  640x480 (0x76) 30.240MHz -HSync -VSync
        h: width   640 start  704 end  768 total  864 skew    0 clock  35.00KHz
        v: height  480 start  483 end  486 total  525           clock  66.67Hz
  640x480 (0x77) 25.175MHz -HSync -VSync
        h: width   640 start  656 end  752 total  800 skew    0 clock  31.47KHz
        v: height  480 start  490 end  492 total  525           clock  59.94Hz
  720x400 (0x78) 28.320MHz -HSync +VSync
        h: width   720 start  738 end  846 total  900 skew    0 clock  31.47KHz
        v: height  400 start  412 end  414 total  449           clock  70.08Hz

While xrandr correctly detects the resolutions of the screen plugged on VGA, using VGA1 only displays a black screen. Note that VGA1 should only use the intel GPU in my configuration and that HDMI-1-1 is working fine without any Xorg configuration (using the nvidia GPU of course).

Software configuration

  • I am trying to use the i915 and nouveau drivers.

  • I have an empty Xorg configuration.

  • I am running Xorg with startx (Xorg is run by my user).

Other tests

Here are the various tests I made without success:

  • I tried to play with the various "echo" commands on /sys/kernel/debug/vgaswitcheroo/switch

  • I tried to use HDMI + VGA with LVDS disabled

  • I tried the proprietary nvidia driver

  • I disabled Optimus in the BIOS: VGA works but I would prefer to consume less power to save my battery

  • I tried some Xorg configuration

  • I tried to run Xorg as root (with needs_root_rights = yes set in /etc/X11/Xwrapper.config)

  • I tried to increase Xorg log level (no error is logged)

  • I tried to blacklist nvidia and nouveau and only use i915: VGA screen is still black

Ressources

In order to understand Optimus, I read the following pages:

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#2 2019-08-27 19:27:53

johnwickxxs v
Member
Registered: 2019-07-12
Posts: 1

Re: Optimus PRIME (i915 + nouveau): black screen on VGA output

Hello , struck on same issue with hdmi . Were you able to solve this

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#3 2019-08-28 07:52:40

V1del
Forum Moderator
Registered: 2012-10-16
Posts: 7,256

Re: Optimus PRIME (i915 + nouveau): black screen on VGA output

With the same hardware? If not don't hijack nor necrobump threads, open up your own, read https://wiki.archlinux.org/index.php/NVIDIA_Optimus before you do.

Closing.

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