Arch Linux

jmsardev

Member

Registered: 2019-02-07

Posts: 12

AMD Navi GPU: System wont boot if screen is off and having flickering

Hello there.

Just a couple of problems I have with my Arch install:

1. System wont boot if the screen/monitor is nor turned on when booting:

If I try booting my system with the monitor off, (I regularly just turn on the computer and turn on the monitor after some time expecting to find the login screen) I receive this message:

[drm:dcn20_init_blank [amdgpu]] *ERROR* DC: failed to blank crtc!

Then I have to reboot with the screen on to get it working. I know I can fix it by turning on the monitor, but maybe there is something wrong I should look into.

2. Flickering, but only sometimes

Looks like sometimes (Can't reproduce exactly, seems to be when gaming and sometimes watching Youtube videos on fullscreen) the screen will flicker with a white bar around the top of the screen. This happens with both Xorg and Wayland, I have tried with FreeSync on and off and locking the refresh rate to 60Hz instead of 75Hz and the same.

Hoping I can get some help. Thanks a lot to all of you!

beaverusiv

Member

From: Taupo, New Zealand

Registered: 2011-07-09

Posts: 41

Re: AMD Navi GPU: System wont boot if screen is off and having flickering

I am having the same issues with my new 5700 XT. I find if I turn on my monitor after the computer it is blank, but if I type in my password when it should've gotten to the login screen the monitor will turn on when logging in.

DerGatt

Member

Registered: 2014-01-25

Posts: 6

Re: AMD Navi GPU: System wont boot if screen is off and having flickering

I have the same issue with a 5700. I get a black bar instead of a white one. And I couldn't find any hints how to investigate any further.

Ropid

Member

Registered: 2015-03-09

Posts: 1,069

Re: AMD Navi GPU: System wont boot if screen is off and having flickering

That problem about having to reboot might be something about the display manager and not caused by the driver. On my Polaris card here, and using LightDM as a display manager, I need to have a script running in the background that looks for monitor changes. The script runs "xrandr -auto" to enable a new display. Without that script, LightDM will not work if I boot with the monitor off and then later power it on.

My LightDM setup looks like this:

I created these three scripts here:

$ cat /etc/lightdm/xrandr-auto.sh 
#!/bin/bash

#trap 'kill -- $(jobs -p)' EXIT
trap 'pkill -P $$' EXIT

LC_ALL=C xev -root -event randr |
while read -r line; do
    # trigger only on certain lines
    if [[ $line == "RRScreenChangeNotify event"* ]]; then
        echo "$(date +%H:%M:%S.%N): screen change event"
        # don't start multiple background jobs
        if [[ ! $(jobs) ]]; then
            {
                # in background: sleep a bit and run xrandr --auto
                sleep 1;
                echo "$(date +%H:%M:%S.%N): run xrandr"
                xrandr --auto
            } &
        fi
    fi
done

$ cat /etc/lightdm/display-setup 
#!/bin/bash
/etc/lightdm/xrandr-auto.sh &

$ cat /etc/lightdm/session-setup
#!/bin/bash
pkill -x xrandr-auto.sh

And then inside "/etc/lightdm/lightdm.conf", things look like this:

[Seat:*]
display-setup-script=/etc/lightdm/display-setup
session-setup-script=/etc/lightdm/session-setup

The following packages have to be installed for the scripts to work:

$ pacman -Qo xev
/usr/bin/xev is owned by xorg-xev 1.2.4-1

$ pacman -Qo pkill
/usr/bin/pkill is owned by procps-ng 3.3.16-2

$ pacman -Qo xrandr
/usr/bin/xrandr is owned by xorg-xrandr 1.5.1-2