Are AMD laptop discrete gpus good in linux?

Waffelson@lemmy.world to Linux@lemmy.ml – 61 points –

I want to buy used laptop with rx6600m and r7 5800h
Does switch between discrete gpu and apu work on linux for amd gpus?
Maybe there are some pitfalls?

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Most gaming laptops these days don't do GPU switching anyways. They do render offloading, where the laptop display is permanently connected to the integrated GPU only. When you want to use the discrete GPU to play a game, it renders the game frames into a framebuffer on the discrete GPU and then copies the completed frame over PCIe into a framebuffer on the iGPU to then output it to the display. On Linux (Mesa), this feature is known as PRIME. If you have two GPUs and you do DRI_PRIME=1 , it will run the command on the second GPU, at least for OpenGL applications. Vulkan seems to default to the discrete GPU no matter what. My laptop has an AMD iGPU and an NVIDIA dGPU and I've been testing the new NVK Mesa driver. Render offloading seems to work as expected. I would assume the AMD Mesa driver would work just as well for render offloading in a dual AMD situation.

On Linux (Mesa), this feature is known as PRIME.

OH THAT'S WHY IT'S CALLED OPTIMUS

I think it's the other way around. NVIDIA's marketing name for render offloading (muxless) GPU laptops is NVIDIA Optimus so when the Mesa people were creating the open source version they called it PRIME.

Yeah, hybrid graphics is a blessing. I have an Intel iGPU for Wayland/VA-API and Nvidia offload for Steam and it's great.

Out of curiosity, how does this work with an external display? Does your HDMI/DisplayPort out go via the dGPU, or is it still done in the same way?

Most of the laptops I've seen the external port is connected to the dGPU.