I am having some problems that I think are issues in the amdgpu driver.
I started playing with Fedora 35 kde installed on removable media on a computer with a Radeon 5500, mainly because I hope to buy a new graphics adapter for my actual Fedora 35 kde system and want to know whether Radeon will work well for me.
Both systems have multiple displays on one graphics card. The one that currently has a Radeon has four displays.
The liveUSB I started from had several malfunctions that looked like issues with having four displays. It took a few reboots to get beyond that.
In a fairly small amount of use, the install I have now has randomly dropped the ability to display contents of two of four displays a few times. Bizarrely, the mouse cursor can still display and move on those displays. But the displays are otherwise black. Dragging a window around on those displays shows only the mouse cursor, not the window being dragged (but the window is intact when dragged back to the working displays). Once I managed to get the displays back by disabling and reenabling them in system settings. But another time that didn’t work and I needed to reboot.
Is there a better driver that will fix this? With online searches I can only find obsolete instructions for closed source radeon drivers, not current instructions.
My past Linux experience has all been with seriously obsolete Nvidia cards, including the card I want to replace in my Linux machine. In all cases (several different cards in different computers but all obsolete Nvidia) the Nouveax driver is always a hopeless pile of crashes, while the oldest architecture version of the closed source Nvidia driver mostly works.
Reading online would make me expect the amdgpu driver should be reliable for the 5500, and I can’t be the only one trying to use four displays. But it sure acts like problems that in my past experience were driver bugs.
With multi-monitor, there are some stuffs need to be aware of, both on the hardware and settings.
For example multi-monitor with HDMI connection. We should know for sure the spec of our HDMI cables transfer rate. This transfer rate will determine the refresh rate. It doesn’t mater what are our monitor spec, if the HDMI cable have low transfer rate then most likely we will get sluggish display on high resolution.
For the settings perspective, let say we using window manager instead of DE. In wayland we need also to specified the X coordinate (if it stacked horizontally) of non-primary monitor correctly or it will overlapping each other.
Thankyou, but I can’t see how any of that is relevant to the problem I described.
I’m not bothered by the time it takes display contents to change. I’m not using these computers for gaming. The display update speed is OK for my uses even with four at 2560x1440. I am also not bothered by the refresh rate (I think Windows and Linux were both using 60 Hz and I didn’t mess with that).
The problem is with two of them going black (except for mouse cursor) as I described.
The system that currently has the 5500 is normally windows. It took me quite a bit of registry tweaking to get it working right in Windows (but the malfunctions before that were nothing like the malfunction I described here). In the current cable arrangement, it has been very robust in windows for a long time, so I don’t think I this is a hardware problem.
Since you mentioned it, there is one problem I had in both Windows and Linux and only learned the good solution for Windows: When using the mouse to drag the displays to align them, it (both windows and whatever installed with kde) seems to have a snap to wrong position feature. Windows 7 had the feature that if you stop near a perfect alignment it would snap to perfect (so if you wanted near perfect for some bizarre test, you needed a registry edit). Windows 10 and whatever it is in this Linux seem to have the opposite feature: Stop at or near perfect and it snaps to a worse alignment. In Windows I’ve known the right registry edit to change the coordinates to whatever I want. In Linux, I don’t know.
In whatever manages that in the Fedora kde spin (using amdgpu), what file holds the coordinates I got from that snapping to slightly wrong, so I can edit it to be perfectly aligned?
I never modify config file in KDE (never look in too), but it should be in ~/.local/share/kscreen/* folder.
With Gnome in ~/.config/monitor.xml, there <x></x> and <y></y> xml tag to determine the coordinate of each monitors. There also other option like resolution and refresh rate.
I still hope to get an answer on the original question I asked.
But I did correctly guess which were the correct files in ~/.local/share/kscreen and edited one of them changing a 1439 to 1440 to eliminate the one pixel overlap I had on this computer (not the same computer I have the original problem on). Later I expect to fix similar overlap on the other computer. There were more files in ~/.local/share/kscreen than I expected. I didn’t figure out what the extra ones represented but I did easily guess which ones are in effect now.
I also didn’t figure out how to make my edit to one of those files take effect. I ended up rebooting to get the effect. I assume a much less drastic method exists.