Arch Linux

icemanx7

Member

Registered: 2015-06-18

Posts: 2

No display after PC reboot and monitors off then switched back on

Hey guys,

I'm having this issue where if my PC is power down/or rebooting but my monitors are off or unplugged, then when I switch them on or plug them in there's no display. Only when I reboot when they are on or plugged does it work again. Any ideas how to fix this?

Using Latest KDE wayland with a 9070xt

cryptearth

Member

Registered: 2024-02-03

Posts: 1,999

Re: No display after PC reboot and monitors off then switched back on

how EXACTLY are your screens connected?
- interface type (display-port, hdmi, dvi, vga, dp-over-usb/-thunderbolt)
- any adapters (like from a dvi-a to vga)
- cable types (if you convert from one interface to another, like from display-port to hdmi/dvi, are you use active or passive cables/adapters)
- why switching off the displays at all? all devices these days go into stand-by - pushing the "power" button just switches to a deeper sleep state but does not fully power off / physical disconnect
- if you try to "save" energy: don't - even with very high rates stand-by merely costs a few bucks over a whole year - if you really want to do it get an extension with a physical switch

overall: display-port is actually a bit picky about connecting after boot (see several LTT videos about it) - so if you use DP you better off with ensuring the screens are on / in stand-by

icemanx7

Member

Registered: 2015-06-18

Posts: 2

Re: No display after PC reboot and monitors off then switched back on

- Screens are connected via DP no adapters
- The cables are brand new and high quality ones
- So I don't usually switch of my monitors I just happened to do it 2 days ago but this issue happens when I plug in a new monitor for example. I have to restart then for the monitor to get picked up

So based of this I'm guessing it's a DP issue and not Arch/Linux?

seth

Member

From: Don't DM me only for attention

Registered: 2012-09-03

Posts: 73,632

Re: No display after PC reboot and monitors off then switched back on

my monitors are off or unplugged

How many? Which specifically? Are they TVs?
You're also NOT using any KVM?

happens when I plug in a new monitor for example. I have to restart then for the monitor to get picked up

After attaching an output that's not being picked up run and post

for OUT in /sys/class/drm/card*; do echo $OUT; edid-decode $OUT/edid; echo "================="; done

You'll need https://archlinux.org/packages/extra/x86_64/v4l-utils/
and also identify the monitor you're expecting to see.

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cryptearth

Member

Registered: 2024-02-03

Posts: 1,999

Re: No display after PC reboot and monitors off then switched back on

So based of this I'm guessing it's a DP issue and not Arch/Linux?

it's at least not uncommon that DP can behave weirdly when not connected and/or not powered during boot
as mentioned: it's a somewhat re-occuring meme at LTT and other tech YT: when a DP connected screen doesn't work properly at first the common solution is to restart the system "for DP reasons"
from what i understand this seem to be related to the initial handshake which for whatever reason can and often does fail when hot plugged after boot