Multi-monitor setup doesn't work properly

ptkato · 2021-08-27 22:15:23

I got a 4th monitor, and it's struggling to keep itself on. I tried different cables and lowering refresh rates to no avail, sometimes it works, but then it turns off after a while; I even tried plopping in another video card in the second pcie slot. I swapped cables between monitors, as well trying with new cables. I also tried to lower the refresh rate from 60Hz to 50Hz in all monitors, to see if that helped, but then all the monitors flickered after like 2 minutes and went automatically back to 60Hz. Considering that I have a RX6700XT, I would assume that it has the power to deal with at least 4 monitors effortlessly, since it has 3 DisplayPort and 1 HDMI outputs. I'm using 3 DisplayPort and 1 HDMI monitors, by the by.

The monitor that is struggling is on DisplayPort. If I leave it connected, it seems to randomly come back to life for a few seconds before dying again. I also tried connecting this monitor with HDMI to a second video card, it worked fine for 1~2 days, then it died once again. The fact that it sometimes work makes me think that it could be a software problem. What could be causing this? What are my options?

From a quick look at `dmesg`, I got a few errors:

[drm:retrieve_link_cap [amdgpu]] *ERROR* retrieve_link_cap: Read dpcd data failed.
[drm:dc_link_detect_helper [amdgpu]] *ERROR* No EDID read.

I'm under linux-5.13.12, GNOME 40.4.0, Wayland.

seth · 2021-08-27 23:40:19

1. Try to disable DPMS, the output might simply not like it
2. disable audio and powermanagement in amdgpu, add the following kernel parameters

amdgpu.audio=0 amdgpu.dpm=0 amdgpu.aspm=0 amdgpu.runpm=0 amdgpu.bapm=0

3. Rather than lowering the frequency, lower the pclk, https://wiki.archlinux.org/title/Xrandr … esolutions - https://aur.archlinux.org/packages/cvt12-git/ will help to generate them ("cvt12 <width> <height> <hz> -r")

Edit: is the output daisy-chained?
Eg. https://bbs.archlinux.org/viewtopic.php?id=259654

Last edited by seth (2021-08-27 23:43:00)

ptkato · 2021-08-28 00:06:41

seth wrote:

1. Try to disable DPMS, the output might simply not like it

It seems that disabling DPMS did nothing.

seth wrote:

2. disable audio and powermanagement in amdgpu, add the following kernel parameters
amdgpu.audio=0 amdgpu.dpm=0 amdgpu.aspm=0 amdgpu.runpm=0 amdgpu.bapm=0

That made all my other monitors turn off.

seth wrote:

3. Rather than lowering the frequency, lower the pclk, https://wiki.archlinux.org/title/Xrandr … esolutions - https://aur.archlinux.org/packages/cvt12-git/ will help to generate them ("cvt12 <width> <height> <hz> -r")

How would I achieve that? When the monitor is not working, I don't even have an output, it's like if it weren't connected at all.

seth wrote:

Edit: is the output daisy-chained?
Eg. https://bbs.archlinux.org/viewtopic.php?id=259654

It's not. Each monitor is connected to their own output in the video card, all 4 monitors are the same model, if that makes any difference.

Last edited by ptkato (2021-08-28 00:07:21)

seth · 2021-08-28 05:50:40

How would I achieve that? When the monitor is not working, I don't even have an output

sometimes it works, but then it turns off after a while

But that's only for X11 anyway - not for wayland.

That made all my other monitors turn off.

"nice"
Is there a "------------[ cut here ]------------" line before the "retrieve_link_cap: Read dpcd data failed" error? (Or general context of what is happening around it, eg. binding the audio component)
Does this work?

amdgpu.ppfeaturemask=0xffffbffb amdgpu.dpm=0

Finally, is the output freesync capable https://wiki.archlinux.org/title/Variable_refresh_rate and do you get the same behavior on
a) the linux console (multi-user.target)
b) X11

ptkato · 2021-08-28 17:15:38

seth wrote:

"nice"
Is there a "------------[ cut here ]------------" line before the "retrieve_link_cap: Read dpcd data failed" error? (Or general context of what is happening around it, eg. binding the audio component)

From what I remember, it didn't have that, is there any other place to check other than `dmesg`? I restarted the computer several times already.

seth wrote:

Does this work?

amdgpu.ppfeaturemask=0xffffbffb amdgpu.dpm=0

Same as before, no image on any monitor. I tried the ppfeaturemask by itself too, no difference.

seth wrote:

Finally, is the output freesync capable https://wiki.archlinux.org/title/Variable_refresh_rate and do you get the same behavior on
a) the linux console (multi-user.target)
b) X11

Yes, the monitors support adaptative sync; and this behaviour is also shown in the linux console and in X11.

seth · 2021-08-28 19:29:37

sudo journalctl -b -1

will show you the journal from the last boot (increase the digit to get older boots)

the monitors support adaptative sync

https://bugzilla.redhat.com/show_bug.cgi?id=1963046
https://wiki.archlinux.org/title/Variab … _on_AMDGPU

Can you disable the feature in the monitor?

ptkato · 2021-08-29 03:56:56

seth wrote:

sudo journalctl -b -1
will show you the journal from the last boot (increase the digit to get older boots)

I found no "cut here" thingy, this is the excerpt from journalctl that contains the errors
https://paste.debian.net/hidden/697ccc0f/

seth wrote:

https://bugzilla.redhat.com/show_bug.cgi?id=1963046
https://wiki.archlinux.org/title/Variab … _on_AMDGPU
Can you disable the feature in the monitor?

There's no option to disable adptive sync in the monitors themselves.

seth · 2021-08-29 07:32:41

Looks like
https://bugzilla.kernel.org/show_bug.cgi?id=211033
https://gitlab.freedesktop.org/drm/amd/-/issues/1492
… again?

Since you're on wayland, how exactly did you go for "disabling DPMS [did nothing]"?
Does it happen on the lts kernel (that's a blind shot, idk whether the commit is reverted there or not)

ptkato · 2021-08-29 18:33:37

seth wrote:

Looks like
https://bugzilla.kernel.org/show_bug.cgi?id=211033
https://gitlab.freedesktop.org/drm/amd/-/issues/1492
… again?
Since you're on wayland, how exactly did you go for "disabling DPMS [did nothing]"?
Does it happen on the lts kernel (that's a blind shot, idk whether the commit is reverted there or not)

To disable DPMS, I went to the GNOME's settings and disabled all power saving features, I also followed this
https://wiki.archlinux.org/title/GDM#GD … ME_3.28.29

Regarding the LTS kernel, it didn't even boot, I just got a blinking _ cursor.

seth · 2021-08-29 21:15:24

I'm not sure this will actually deactivate DPMS, you could try that in X11, because the logs look a lot like that?

ptkato · 2021-09-08 19:11:15

Oki, I got a DisplayPort to HDMI cable, plugged the DisplayPort side on the video card, and the HDMI side on the monitor, and it worked first try. There must be a very odd interaction between this monitor model specifically and the DisplayPort, while two of my monitors display this behaviour, the other two don't. And mind you, the DisplayPort input does work, because I was using it before this whole debacle.

Arch Linux

#1 2021-08-27 22:15:23

Multi-monitor setup doesn't work properly

#2 2021-08-27 23:40:19

Re: Multi-monitor setup doesn't work properly

#3 2021-08-28 00:06:41

Re: Multi-monitor setup doesn't work properly

#4 2021-08-28 05:50:40

Re: Multi-monitor setup doesn't work properly

#5 2021-08-28 17:15:38

Re: Multi-monitor setup doesn't work properly

#6 2021-08-28 19:29:37

Re: Multi-monitor setup doesn't work properly

#7 2021-08-29 03:56:56

Re: Multi-monitor setup doesn't work properly

#8 2021-08-29 07:32:41

Re: Multi-monitor setup doesn't work properly

#9 2021-08-29 18:33:37

Re: Multi-monitor setup doesn't work properly

#10 2021-08-29 21:15:24

Re: Multi-monitor setup doesn't work properly

#11 2021-09-08 19:11:15

Re: Multi-monitor setup doesn't work properly

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