Refresh rate reduced on screens wired to a dGPU (Wayland)
Hello and good day,
first I hope I'm at the right address to report this. If not I'm happy for suggestions
Brief summary of the problem:
The output on screens connected to the ports that are wired to the dGPU always gets rendered at a reduced refresh rate than the screen is set to.
Example of my 4k@60 screen, connected to a port wired to the dGPU:
- The screen is set to 60Hz, the image gets rendered at 30Hz.
- The screen is set to 30Hz, the image gets rendered at 15Hz.
The screens connected to the iGPU render properly (internal one and the port wired to it) at the full refresh rate.
We can confirm this happens on AMD / AMD and AMD / Nvidia laptops (haven't yet tested this with an Intel machine).
This phenomenon does not happen while using X11.
Launching radeontop
does not change the situation like described here: #2191 (when watching the iGPU or the dGPU)
Hardware description:
Machine 1:
Linux 5.18.11-200.fc36.x86_64 #1 SMP PREEMPT_DYNAMIC Tue Jul 12 22:52:35 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux
CPU: AMD Ryzen 9 6900HS with Radeon Graphics (family: 0x19, model: 0x44, stepping: 0x1)
GPUs:
03:00.0 VGA compatible controller [0300]: Advanced Micro Devices, Inc. [AMD/ATI] Navi 23 [Radeon RX 6650 XT] [1002:73ef] (rev c0)
07:00.0 VGA compatible controller [0300]: Advanced Micro Devices, Inc. [AMD/ATI] Rembrandt [Radeon 680M] [1002:1681] (rev c7)
Machine 2:
Linux 5.18.5-arch1-g14-1 #1 SMP PREEMPT_DYNAMIC Tue, 21 Jun 2022 19:32:52 +0000 x86_64 GNU/Linux
CPU: AMD Ryzen 9 5900HS with Radeon Graphics (family: 0x19, model: 0x50, stepping: 0x0)
GPUs:
01:00.0 VGA compatible controller: NVIDIA Corporation GA106M [GeForce RTX 3060 Mobile / Max-Q] (rev a1)
07:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Cezanne (rev c4)
- Display(s):
- internal display: 2560x1600@120Hz
- external display: 4k@60Hz (via HDMI or USB-C DP)
- Type of Display Connection: HDMI or USB-C DP