https://bugs.freedesktop.org/show_bug.cgi?id=110510
Bug ID: 110510 Summary: Radeon VII HDMI issues: Flicking/system crashing Product: DRI Version: XOrg git Hardware: Other OS: All Status: NEW Severity: normal Priority: medium Component: DRM/AMDgpu Assignee: dri-devel@lists.freedesktop.org Reporter: tom@r.je
Created attachment 144089 --> https://bugs.freedesktop.org/attachment.cgi?id=144089&action=edit dmesg after setting HDMI screen to 59.94hz
I have a radeon VII with two 4k displays. One connected via HDMI and one connected via DisplayPort. Neither monitor supports freesync.
Linux 5.0.9 Mesa 19.0.3
The DisplayPort monitor is working fine.
The HDMI monitor has some problems. On its own I can get it working perfectly. Here's the output from xrandr:
DisplayPort-2 connected primary 3840x2160+0+0 (normal left inverted right x axis y axis) 521mm x 293mm 3840x2160 60.00*+ 30.00 30.00 24.00 29.97 23.98 1920x1200 60.00 1920x1080 60.00 50.00 59.94 30.00 24.00 29.97 23.98 1600x1200 60.00 1680x1050 59.95 1280x1024 75.02 60.02 1440x900 59.89 1280x960 60.00 1280x800 59.81 1152x864 75.00 1280x768 59.87 1280x720 60.00 50.00 59.94 1024x768 75.03 70.07 60.00 832x624 74.55 800x600 72.19 75.00 60.32 56.25 720x576 50.00 720x480 60.00 59.94 640x480 75.00 72.81 66.67 60.00 59.94 720x400 70.08 HDMI-A-0 connected 3840x2160+3840+0 (normal left inverted right x axis y axis) 521mm x 293mm 3840x2160 60.00*+ 60.00 50.00 59.94 30.00 30.00 24.00 29.97 23.98 1920x1200 60.00 1920x1080 60.00 50.00 59.94 30.00 24.00 29.97 23.98 1600x1200 60.00 1680x1050 59.88 1280x1024 75.02 60.02 1440x900 59.90 1280x960 60.00 1280x800 59.91 1152x864 75.00 1280x768 59.87 1280x720 60.00 50.00 59.94 1024x768 75.03 70.07 60.00 832x624 74.55 800x600 72.19 75.00 60.32 56.25 720x576 50.00 720x480 60.00 59.94 640x480 75.00 72.81 66.67 60.00 59.94 720x400 70.08
If it's connected on it shows two problems intermittently:
1. It flickers occasionally with visual artifacts 2. The screen goes black for a few seconds then comes back
With just the HDMI screen connected this can be solved. If I set the refresh rate to 59.94 the problems go away and everything is working flawlessly.
However, as soon as I connect the second monitor by displayport this fix no longer works.
With both monitors connected and both running at 60.0hz, the displayport screen is fine but the HDMI screen flickers. An easy fix I thought: Run the HMDI screen at 59.94hz and the flicker will go away.
Unfortunately, what actually happens is the entire session freezes after a few seconds on both X and Wayland. Usually it requires a complete system reset but I have managed to recover from it a couple of times and I've attached my dmesg output.
Sometimes the freeze is instant, other times I get up to 10 seconds before the system freezes.
I also tried 50hz on the HDMI monitor and the same thing happened.
There appears to be two different issues here:
1. HDMI flickers 2. Running two monitors at different refresh rates causes the driver to crash