Having another little issue with my new monitor. I switched the connection from a HDMI cable to a DP one, as there are a few improvements to using DisplayPort instead. This introduces a small annoyance I don’t know how to fix.
Whenever the monitor goes into standby, it only stays that way for a few seconds before turning itself back on. Power Management - Energy Saving - Screen Energy Saving is set to 5 minutes; The OS does indeed power the monitor off after this idle time and I even see its power LED indicating that. However it only stays this way for roughly 6 - 8 seconds: Despite not moving the mouse or pressing any key, the monitor always powers back on after this amount before I do so. The problem only started after changing the cable type.
Anyone else experiencing this issue and knows how to solve it? Is this perhaps a kernel / X11 bug that I should report? openSUSE Tumbleweed x64 KDE, amdgpu module, monitor is a ViewSonic VX2758-C-MHD 23.6.
It has two settings in that regard: Auto Power Off and Sleep, the later giving me large intervals as an option (30 minutes, 60 minutes, etc). I tried enabling them both but it doesn’t affect the issue unfortunately.
Here are the X11 power settings too, in case something should be tweaked here as well. It should be noted the monitor is marked as being Energy Star compliant from what I could find.
mircea@linux-qz0r:~> xset q
auto repeat: on key click percent: 0 LED mask: 00000000
00: Caps Lock: off 01: Num Lock: off 02: Scroll Lock: off
03: Compose: off 04: Kana: off 05: Sleep: off
06: Suspend: off 07: Mute: off 08: Misc: off
09: Mail: off 10: Charging: off 11: Shift Lock: off
12: Group 2: off 13: Mouse Keys: off
auto repeat delay: 660 repeat rate: 25
auto repeating keys: 00ffffffdffffbbf
bell percent: 50 bell pitch: 400 bell duration: 100
acceleration: 2/1 threshold: 4
prefer blanking: yes allow exposures: yes
timeout: 0 cycle: 600
default colormap: 0x20 BlackPixel: 0x0 WhitePixel: 0xffffff
DPMS (Energy Star):
Standby: 300 Suspend: 450 Off: 600
DPMS is Enabled
Monitor is On
Server does not have the FontCache Extension
Now that I’ve permanently switched from X11 to Wayland I decided to do a few more tests. Via HDMI cable, the monitor will go into standby properly including on WL! Unfortunately I need to use DisplayPort for a few reasons… such as the HDMI connection only working at 120 Hz instead of the full 144 Hz, while also requiring me to boot with “amdgpu.dc=0” else the monitor won’t turn on through this cable. It appears whatever the issue is, clearly only DP is affected… is it even the monitor’s fault or a Kernel bug in the end? Does Wayland offer any monitor power management settings I can play with? I really don’t wish to wear my monitor out nor waste electricity by keeping it turned on throughout the night… and I can’t manually power it off either since if I do Wayland will freak out that there’s no display and crash the session to the login screen, or switch to my VR headset as a primary display making it impossible to see anything and bring my monitor back on without rebooting.
To be fair I don’t quite know: I got a simple one from a nearby store thinking it wouldn’t make a difference. Only info I can find so far is a label on it, photo below. On the official page of my exact monitor model, it suggests DisplayPort 1.2 is used… I’m thus assuming that as long as the cable is at least 1.2 itself, which it should be unless it’s some crazy ancient model, that shouldn’t make a difference.
Any new thoughts on this please? I really don’t wish to leave my monitor on during the night like that. If I could I’d use the HDMI cable which doesn’t have this issue, but I can only use the monitor in 120 Hz mode over HDMI not 144 Hz like DP. Perhaps a different driver or kernel module is used for DisplayPort which isn’t properly sending the standby signal to the monitor?
Have you tested using DP with 120 instead of 144? If it behaves so configured, I’d think you found a(nother) bug to blame on Wayland that likely needs reporting upstream. I’m guessing not many testers or developers running 144 with 1080P on Wayland.
WRT overnight, what about switching to empty login screen on vtty3 before off to bed?
Another thought - what happens if connecting both HDMI and DP cables? I don’t know if I’d want to try on a display that isn’t under warranty, but yours is new. Does it have a manual that says don’t do that?
What if you try a live Fedora 32 stick boot, same problem with 144?
Interesting suggestion: I didn’t try putting the monitor in standby over DP at 120 Hz, didn’t think that would make a difference. Might give that a go next… thanks.
One thing to clarify: This issue exists on both X11 and Wayland (always KDE Plasma). In both cases HDMI will properly go and stay in standby, but DP will fully cut off the signal instead. This makes me suspect it could be an amdgpu or other kernel issue.
Tried enabling standby on both 120 Hz and 60 Hz, no difference. Also set the monitor to request the YUV color format too but this didn’t help either.
Anything else? I’d really appreciate more input from anyone who: Uses openSUSE Tumbleweed, an AMD card on the amdgpu module, an 144 Hz monitor, and is connecting their monitor via DisplayPort… should be common things and hopefully a known bug somewhere.
Edit: It appears another OS-TW user posted about the exact same problem with the same hardware and configuration as me. No responses to their thread yet but I’m clearly not the only one.