• Uknown display when connection second screen

    Since a short time antergos doesn’t recognise my external displays anymore. I have connected 5 different screens but all of them is saying “unknown display”. The big problem is i can’t select any resolution higher then 1024x768. This is very annoying. I think 2 or 3 weeks ago everything just worked fine but now i have this problem with all kind of screens (but not my laptop screen). Xrandr give me exact the same output. Even when i add manual a resolution to the VGA1 port i can’t switch to it. The screen turns black for a moment and then it’s exactly the same old resolution.
    Can someone help me further with this? I really don’t know what to do.

  • Hi,

    It sounds like a kernel bug. Try installing the LTS kernel, boot with it, and see if the problem persists.

    sudo pacman -S linux-lts
    sudo grub-mkconfig -o /boot/grub/grub.cfg
  • Hi,

    Still doesn’t work. And i have 2 other problems now: booting is slower and my laptop can’t suspend anymore.

  • What’s the output of: lspci -k | grep -A 2 -E "(VGA|3D)"

  • lspci -k | grep -A 2 -E “(VGA|3D)”
    00:02.0 VGA compatible controller: Intel Corporation Mobile 4 Series Chipset Integrated Graphics Controller (rev 07)
    Subsystem: Hewlett-Packard Company Device 30db
    Kernel driver in use: i915

    My graphics card is a Mobile Intel GMA 4500MHD (really old one )

  • Try configuring it to use UXA instead of SNA as outlined here:


  • I did but still not working :(.
    I added a own resolution to the VGA1 port (full hd) and it’s working. I have a full hd output on my vga port and i see it on my monitor, but… the colors are awfull. I just don’t understand why my screens aren’t detected suddenly.

  • It is very strange. If they suddenly stopped working that would mean its something to do with a kernel update. However, that should also mean that the LTS kernel would not have the same issue. Please post your logs here and I’ll take a look. Thanks.

  • I think the problem is worser then i though… I’ve tried a live antergos usb but the same problem: the screen is still not recognised. Also on a elementary and lubuntu live usb… I think this is a hardware issue :(.

  • When i’m searching around the web i see more users (windows) have had the same problem with an external monitor… And nobody really had a solution.
    A little question, how can i switch back to the old kernel? Because this one is slower and my laptop can’t suspend anymore.

  • All you have to do is select the other kernel from the grub menu at boot.

display51 screen18 xrandr3 uknown1 Posts 12Views 4003
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