So now i know the correct way to do this, i can confirm it works, not sure its necessarily a better way, but thanks! :O)

definitely try from the terminal either as user of sudo -i

i have my passthrough GPU working on my hybrid intel CPU i7+GPU 620/AMD R7 GPU laptop. although it doesnt show the GPU selectable in the Opencl system properties, when i am using EEvEE, cycles GPU and Luxcore GPU it works on any Blender v2.80 to v2.92 was the following:

for my laptop, my radeon gpu is a passthrough from the intel on chip GPU for example on fedora 32 i had to add to my Grub file

i have since 2.90.1+ been able to use the commanline DRI_PRIME=1 /home/yourloginname/blender-2.91.0/blender and have had no more freezes or crashes experienced before, for the last month i have been able to use all blender versions like this. this needs to be out there for others to run blender without freezing on multiGPU laptops.

i'm only able to use B282a at this stage everything newer is having problems with stability, it will freeze even with the factory defaults loaded, i have tried multiple versions and cant replicate exactly when it will freeze, it can be as simple as changing a value regardless of the mode, or render engine used, it seems to be a vram thing with either AMD GPU or INTEL passthrough to AMD GPU hybrids at this stage.

Here are some files for system info from Blender with screenshots

when it works like in B2.82a it works well, i have also tested Luxcore 2.3 on B2.82a/2.83.5/2.90a/2.91 and it works fine on CPU, iv've also tried Luxcore 2.5 and choosing GPU crashes blender in the latest 2.90/2.91 so thats interesting, it also doesnt show the GPU in device list.

In T71258#1004021, @tsukirockstar wrote:

@gary stocker (gary) Parris
Sorry. I might have confused your card model (not very familiarized with laptops..) But I reproduced this on Fedora, Ubuntu and windows. And yet again, Not only poor performance on the viewport using cycles. But is a persistent issue across more than one distro and OS.

On my case, as I said, the viewport goes brutally faster with my core I9 than with a RX 590 8GB. also tested with a RX580. Both have Polaris architecture. Both fail with volumes.

You can check the screenshots that I posted. Right now, I'm using EEVEE and avoiding cycles.

If someone can reproduce this with the same or similar (Polaris) AMD cards would be nice and a step forward.

You are wrong assuming that is a "fedora combo issue" IT IS NOT.

yet again, if no one reproduces the issue we'll never know. I already posted what I know. BTW: I still have this issue and right now I'm using windows...

I'll hit the bed. Bye.

In T71258#1004007, @tsukirockstar wrote:

I'm still getting this issues on: Fedora 32, Ubuntu and Windows 10. All of them seem to be related to volume scatter.
As for fedora, I'm using amdgpu (open source) and Opencl (from amd) to do it just uncompress the ubuntu/rhel drivers (only the openCl needed stuff) and luxrender works like a charm and so does davinci resolce and darktable.

Ubuntu: No need to get into complications. Just use the AMD privative drivers. Same result. freezes using volume scatter, so any volumetric material crash and burn.. Obviously, this doesn't happens with EEVEE It's using OpenGl. so it works fine even without any aditional driver.

Windows: Same as ubuntu.

@gary stocker (gary) Parris You say that you are using an R7 card? That's an old architecture and even on windows cycles is not supported. I tested it with a R9 270x and I don't have any opencl support, both in windows and Linux.

I recently reproduced the same on centos. So, I would not say that this is fedora only.

One more thing: Nvidia cards won't cause any issue no matter the system, OS, distro. I tested a 150TI and a 1080TI. fine in both cases.

This seems to be related to the polaris architecture of some AMD cards, and that's not good. At all.

I use fedora 32, am using a HP Laptop Intel/Radeon hybrid, set the graphics driver to MESA to start with the AMD R7 m340, Blender 2.82 works with all Open CL and CPU modes for EEVEE, Cycles and Luxrender.

Here are screen grabs from Ubunto which i tried to use 2.90 Alpha on and in different modes maybe it will help, this is using the version downloaded from 16 June 2020

In T76529#953360, @ArbySmith (BlastedPupil) wrote:

I have now tried 2.83 portable version using Wayland and Xorg.
The problem continues but seems to take longer before it hangs the system.

Trying to find a reproducible event but I have yet to find one.
It seems that it may be related to change back to solid view after LookDev or Render view.
Another possibility is toggling back and forth from the ortho/perspective (using 5 on numpad)

I still have had no luck compiling but this might be Fedora specific problem.
I have installed missing libs that compiler could not find but it still fails to find them.

Sorry if the following is a bit of subject but since user is also experiencing a similar hang...

In T76529#953107, @Gary Parris (GAPsWorld) wrote:

...it only works in CPU and doesn't even show my AMD...

i can use 2.82 without crashing but still my GPU doesnt show as available or render in GPU cycles or eevee.

I have also been trying to use on a machine with Intel i5 M 450 and AMD RV710/M92 and although it has
been working it does not show as GPU available in Blender even though inxi shows "direct render: Yes"

Have you had any success compiling in Fedora ?

I have also been having issues with 2.83 & 2.90 of the system hanging, i get mouse abality and can manage to shutdown safely through memorised key presses or using a kill command set up ready for this, but with varying success. a reboot is the only thing possible once blender hang. workbench also freezes!