Intel HD Graphics 520 VGA output

[pa4wdh]

Hi All,

I'm working on an old problem on my laptop, i can work around it, but i got bitten by it again so now i want to solve it.

The problem is that my laptop has HDMI and VGA outputs. On current kernels (now 4.19.52) only HDMI works, the most recent one where VGA also worked is 4.5.1. I'll attach some more info, if you need more please let me know.

lspci:

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00:02.0 VGA compatible controller: Intel Corporation Skylake GT2 [HD Graphics 520] (rev 07)

Kernel 4.19.52:

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uname -a
Linux pc15 4.19.52-gentoo #5 SMP Sat Nov 9 10:56:33 CET 2019 x86_64 Intel(R) Core(TM) i5-6200U CPU @ 2.30GHz GenuineIntel GNU/Linux

dmesg |  grep 915
[    0.920010] i915 0000:00:02.0: vgaarb: changed VGA decodes: olddecodes=io+mem,decodes=io+mem:owns=io+mem
[    0.920520] [drm] Finished loading DMC firmware i915/skl_dmc_ver1_27.bin (v1.27)
[    0.927588] [drm] Initialized i915 1.6.0 20180719 for 0000:00:02.0 on minor 0
[    2.579028] i915 0000:00:02.0: fb0: inteldrmfb frame buffer device

ls -l /sys/class/drm
total 0
lrwxrwxrwx 1 root root    0 Nov  9 11:00 card0 -> ../../devices/pci0000:00/0000:00:02.0/drm/card0
lrwxrwxrwx 1 root root    0 Nov  9 11:00 card0-HDMI-A-1 -> ../../devices/pci0000:00/0000:00:02.0/drm/card0/card0-HDMI-A-1
lrwxrwxrwx 1 root root    0 Nov  9 11:00 card0-eDP-1 -> ../../devices/pci0000:00/0000:00:02.0/drm/card0/card0-eDP-1
lrwxrwxrwx 1 root root    0 Nov  9 11:00 card1 -> ../../devices/platform/vgem/drm/card1
lrwxrwxrwx 1 root root    0 Nov  9 11:00 renderD128 -> ../../devices/pci0000:00/0000:00:02.0/drm/renderD128
-r--r--r-- 1 root root 4096 Nov  9 11:00 version

Here you can clearly see eDP (internal display) and HDMI

Kernel 4.5.1:

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uname -a
Linux pc15 4.5.1-gentoo #21 SMP Sun Aug 20 13:30:15 CEST 2017 x86_64 Intel(R) Core(TM) i5-6200U CPU @ 2.30GHz GenuineIntel GNU/Linux

dmesg  |  grep 915
[    0.376340] [drm] Finished loading i915/skl_dmc_ver1.bin (v1.26)
[    0.388984] [drm] Initialized i915 1.6.0 20151218 for 0000:00:02.0 on minor 0
[    2.613564] i915 0000:00:02.0: fb0: inteldrmfb frame buffer device

ls -l /sys/class/drm
total 0
lrwxrwxrwx 1 root root    0 Nov  9 11:10 card0 -> ../../devices/pci0000:00/0000:00:02.0/drm/card0
lrwxrwxrwx 1 root root    0 Nov  9 11:10 card0-DP-1 -> ../../devices/pci0000:00/0000:00:02.0/drm/card0/card0-DP-1
lrwxrwxrwx 1 root root    0 Nov  9 11:10 card0-HDMI-A-1 -> ../../devices/pci0000:00/0000:00:02.0/drm/card0/card0-HDMI-A-1
lrwxrwxrwx 1 root root    0 Nov  9 11:10 card0-HDMI-A-2 -> ../../devices/pci0000:00/0000:00:02.0/drm/card0/card0-HDMI-A-2
lrwxrwxrwx 1 root root    0 Nov  9 11:10 card0-eDP-1 -> ../../devices/pci0000:00/0000:00:02.0/drm/card0/card0-eDP-1
lrwxrwxrwx 1 root root    0 Nov  9 11:10 controlD64 -> ../../devices/pci0000:00/0000:00:02.0/drm/controlD64
lrwxrwxrwx 1 root root    0 Nov  9 11:10 renderD128 -> ../../devices/pci0000:00/0000:00:02.0/drm/renderD128
-r--r--r-- 1 root root 4096 Nov  9 11:10 version

Here you can see eDP (internal display), 2 HDMI's and a DP (VGA output).

Any ideas on how to troubleshoot this?

[pa4wdh]

Polite bump to see if anyone has any suggestion?