#Linux AMD eGPU sluggish on external monitor (GNOME Wayland)

1 messages · Page 1 of 1 (latest)

halcyon kite
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Hello, I'm having some issues with an eGPU setup with GNOME and Wayland. gnome-shell is extremely sluggish, and so are any applications that run on it, especially those that run on the eGPU
Running glxgears, I see a pretty severe difference between the internal and external monitors. On all GPUs, my laptop display runs it at 60FPS, but when dragging the window over to the display attached to my rx480 it drops to around 30 FPS regardless of the GPU being used
I believe GNOME is using the iGPU for compositing, and so frames rendered on the eGPU are first copied back to the iPGU and then back to the eGPU instead of being directly rendered
Is there a way to change this?

halcyon kite
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Okay, this seems like it's definitely that

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I checked intel_gpu_top and the value goes noticeably up when I run glxgears or another application on the AMD GPU, on the monitor driven by that AMD GPU

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So it seems whatever is rendered comes back through the thunderbolt connection, gets composited by the iGPU, and the entire final frame gets sent over to get rendered

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I will open an issue on the GNOME gitlab about this

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Surprise surprise

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There's already an issue open

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4 years old

mild wagon
halcyon kite
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It's really weird

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I completely power off. Then, I unplug and replug the eGPU. Wait ~10 seconds. Then boot.

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My laptop posts on the eGPU instead of on the internal display, and later the eGPU becomes card0

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Then it's really smooth

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No clue why that's the case, but since I connect/disconnect my laptop once a day it's definitely ok

halcyon kite
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Update: In this state the internal display stutters and GNOME shell is still choppy.