[Solved] Problems with VGA in Skylake integrated graphics

Cokegod · 2015-12-24 19:48:20

My processor is an Intel i7 6700 and my motherboard is an ASRock H170M Pro4. My motherboard has four graphics ports (DisplayPort, HDMI, DVI-D and VGA), I'd like to use the integrated graphics in my processor and connect one monitor to the DisplayPort and one to the VGA.
The problem is that when my PC boots with a display connected to it by VGA it gets stuck after it boots. I see all the systemd output of the boot process but eventually everything turns black and I can't do anything. The DisplayPort on the other hand doesn't have this problem. When I boot with two monitors connected to my PC I get the same result, except only the monitor connected by VGA turns black while the other monitor is still able to display stuff, but everything is still stuck. It should be noted that this problem probably isn't related to Xorg, since it happens even without Xorg automatically starting (I get to a situation where my DisplayPort display shows the login prompt while the other one is all black and I can't do anything).

Here's the output of xrandr (obviously with only one display connected by DisplayPort):

Screen 0: minimum 8 x 8, current 1920 x 1200, maximum 32767 x 32767
DP1 connected primary 1920x1200+0+0 (normal left inverted right x axis y axis) 518mm x 324mm
   1920x1200     59.95*+
   1920x1080     60.00    50.00    59.94    30.00    25.00    24.00    29.97    23.98  
   1920x1080i    60.00    50.00    59.94  
   1600x1200     60.00  
   1280x1024     75.02    60.02  
   1152x864      75.00  
   1280x720      60.00    50.00    59.94  
   1024x768      75.08    60.00  
   800x600       75.00    60.32  
   720x576       50.00  
   720x480       60.00    59.94  
   640x480       75.00    60.00    59.94  
   720x400       70.08  
HDMI1 disconnected (normal left inverted right x axis y axis)
HDMI2 disconnected (normal left inverted right x axis y axis)
HDMI3 disconnected (normal left inverted right x axis y axis)
VIRTUAL1 disconnected (normal left inverted right x axis y axis)

What's weird is that my motherboard has DisplayPort, HDMI, DVI-D and VGA ports, but xrandr recognizes two extra HDMI and one VIRTUAL (?) port instead of the DVI and VGA ports.

Note that without the 'i915.preliminary_hw_support=1' boot parameter my PC can actually boot with a display connected to it by VGA, but I get many other problems probably related to not having proper driver support (no animations, lower resolution, etc).

Also, I did try Ubuntu 15.10 on this machine before switching to Arch and in Ubuntu the VGA port did work properly.

Last edited by Cokegod (2015-12-26 23:29:27)

Cokegod · 2015-12-26 22:46:06

Ok so I managed to fix it by upgrading my kernel to 4.3 (from testing).

jasonwryan · 2015-12-26 23:28:49

Please remember to mark your thread as [Solved] by editing your first post and prepending it to the title.

Arch Linux

#1 2015-12-24 19:48:20

[Solved] Problems with VGA in Skylake integrated graphics

#2 2015-12-26 22:46:06

Re: [Solved] Problems with VGA in Skylake integrated graphics

#3 2015-12-26 23:28:49

Re: [Solved] Problems with VGA in Skylake integrated graphics

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