Display not detected after reboot - AMD

Question

I have performed an update via apt-get and, after the reboot, one of the displays is not detected anymore. Both the displays I have work, but they simply mirror each other.

I have tried via Displays settings but only a ''built-in display'' is detected.

My system's specifics are:

Distributor ID:
Ubuntu Description: Ubuntu 16.04.5 LTS
Release: 16.04
Codename: xenial

Graphic card:
VGA compatible controller [0300]: Advanced Micro Devices, Inc. [AMD/ATI] Lexa XT [Radeon PRO WX 3100] [1002:6985]

Dirvers:

lspci -nnk | grep -i vga -A3
65:00.0 VGA compatible controller [0300]: Advanced Micro Devices, Inc. [AMD/ATI] Lexa XT [Radeon PRO WX 3100] [1002:6985]
Subsystem: Dell Device [1028:0b0c]
65:00.1 Audio device [0403]: Advanced Micro Devices, Inc. [AMD/ATI] Baffin HDMI/DP Audio [Radeon RX 550 640SP / RX 560/560X] [1002:aae0]
Subsystem: Dell Device [1028:aae0]

Thank you for your help.

How many displays do you have? Are they connected through HDMI or VGA? — Gabriel Ziegler, Oct 26 '18 at 14:09

score 0 · Answer 1 · answered Oct 26 '18 at 13:27

0

Use xrandr to manage your displays:

to automatically detect displays:
```
xrandr --auto
```
to set the displays to extend each other you can do something like:
```
xrandr --output YOUR_DISPLAY_NAME --left-of VGA_NAME/HDMI_NAME
```

you can find more at the docs

answered Oct 26 '18 at 13:27

Gabriel Ziegler

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When I type xrandr --auto, I get this message: Failed to get size of gamma for output default. What can it be ? – Davide Chiarugi Oct 26 '18 at 13:53
@DavideChiarugi perhaps you have to add a new mode in xrandr to allow it to detect your other display. What do you see when you type xrandr --output and hit tab to see the available displays? – Gabriel Ziegler Oct 26 '18 at 14:01
The only possible available display that I obtain is "default" – Davide Chiarugi Oct 26 '18 at 14:06
@DavideChiarugi Have a look at this solution – Gabriel Ziegler Oct 26 '18 at 14:10

Display not detected after reboot - AMD

1 Answers1