… then everything returns to normal. This happens several times a day, even in the middle of writing or surfing. There is nothing unusual in the log file. What could it be?
btw: I had been using the same HDMI cable for years with a different distro until recently: this effect never occurred. So I don’t think the HDMI cable is the problem.
It could be caused by power dips or spikes, or perhaps RF interference being picked up by the HDMI cable; my display sometimes does this when the timer for the uplighter clicks on (inductive load, as it’s mercury vapour running via a magnetic ballast).
Regardless, trying a different HDMI cable will tell you something about the issue, even if it merely confirms the old cable is not the problem. It is a tried and true method of Fault finding. The first rule is don’t assume, confirm.
I do have the same issue with both of my monitors but with display port cables and I have a UPS so that should regulate any kind of power issue.
It would be extremely unlikely for both cables to suddenly have issues at basically the same time.
It doesn’t happen too frequently to me, only once or maybe twice a day(rarely) and some days are completely fine.
Some info on my setup from another post, but I do switch to the proprietary driver as well fairly regularly, haven’t noticed if it happens on both driver or one specific one:
I’ve only used manjaro for a couple of months daily and I have other more important issues that need fixing so I haven’t had time to look into this at all since it is a fairly minor annoyance.
Hi @gloewa
Since you’ve already ruled out cables, it might be worth looking at the software side. AMD’s integrated graphics have a power saving feature called PSR (Panel Self Refresh) that’s known to cause exactly this - brief blackouts at random intervals.
I must admit that I have also recently been experiencing this issue, although it hasn’t been enough to bother me, so I haven’t done any chasing up (apart from looking in my system log, which revealed nothing).
Anyway, hopefully @musdus may have found the cause of the issue:
The issue was resolved on an EndeavourOS system by disabling PSR, although it was more than a year ago:
I’m a little surprised that it has suddenly appeared in linux618 - maybe an amdgpu regression?
So, maybe try switching to linux66 to see if that resolves the issue. Don’t switch to anything earlier though, as that may cause another issue - this time with polkit.
If you don’t want to switch to an earlier kernel, then see if disabling PSD via the boot parameters will work.
This can be done by opening the /etc/default/grub file in a text editor such as kate:
kate /etc/default/grub
and adding amdgpu.dcdebugmask=0x10 to the GRUB_CMDLINE_LINUX= line. As it is a system file, kate will prompt you for your password when you save the file.
I am not deeply familiar with the internals here, but based on similar reports this might be related to AMD PSR (Panel Self Refresh). PSR has a history of causing brief, random black screen flickers on AMD iGPUs, often during power-state changes.
If you want to rule this out, you can temporarily disable PSR (no reboot required):
sudo sh -c 'echo 0x200 > /sys/module/amdgpu/parameters/dcdebugmask'
If the issue stops occurring after a few days, it likely points to PSR. In that case you can make it permanent by adding amdgpu.dcdebugmask=0x200 to your kernel parameters.
The file dcdebugmask has read-only permission, even for the root user.
Since this event occurs very rarely, I will make a note of this suggested solution and leave the system unchanged.
I will try the temporarary method first.
