OK, I'm out of time for now, need to go. I need to read through the thread again tonight. My suspicion is that this isn't going to work as QEMU spits out a crash on startup citing something about 32BIT addresses and an unimplemented OPCode.

In OS4 (I have sm501 device as well at the moment) it does show the PCI card as "Working" in HWInfo but I'm guessing that means little more than it knows that it's there.

This is my RX580 incidentally with 8GB of memory on board. Just giving it a try because it was there sat in a box doing nothing.

@geennaam

Ah, ok - same result though, only the GPU and it's embedded Audio are in group 30

@geennaam

if the group is the '0d' in '0d:00.0' then no. Apart from '0d:00.1' which is the HD Audio part of the GPU (also bound to virtio).

I specifically purchased this motherboard at the time based on it's ability to isolate and from memory I believe it puts every device in it's own group. This was pre-pandemic though so my memory of it isn't great.

@geennaam

No problem - I'll try the script but my Ubuntu is 22.04 and I don't desperately fancy reinstalling. Not really an issue though, I've done all of this several years ago on this machine, I just need to dig out my notes and remember how.

Incidentally, on this machine at least, it's possible in the BIOS to have virtualisation enabled (whatever AMD refer to VT-d as) but not have IOMMU isolation enabled. I'll figure it. But maybe not today as I need to go out soon.

[EDIT] Never mind - that was easy, the script worked and my secondary GPU is isolated to vfio-pci

I'm losing track of all the scenarios a bit here but as I mentioned before I have a motherboard with PCI and VT-d but I'm very doubtful that the BIOS will support the required isolation for passthrough as it definitely predates that really being something that end users were into. I may be wrong on the 6700K processor too, I think that machine in on my electronics workbench which means the one in the box is likely 4700K. Still has VT-d though, but even earlier.

On the plus side, I just realised that if I'm to put the spare GPU I have in my main gaming machine then I don't need the missing power cable as it already has one. I'm posting now with both GPUs installed and I know this motherboard has excellent isolation properties if I can remember how to enable it in the BIOS.

So when I get some time I can do some experiments and potentially add some logs etc., but I'll only do so if it looks like it adds value otherwise too much noise is not a good thing!

[EDIT] Forgot to mention that I also have a PCI to PCIe bridge to allow a PCIe card to be plugged into PCI. I was about to send it back as it's the wrong way round (I wanted to plug PCI into PCIe). I'm not sure I really see the point in me keeping it because IF the motherboard with PCI will allow isolation (doubtfull) then that board has PCIe. The only reason to put it into a bridge would be to test the bridge. Like I say, too many scenarios here, I'm losing track!

Lol! Yep. Anything associated with Amiga costs a premium.

One question - isn't Voodoo3 AGP? - never mind, there are PCI versions.

[edit] So what features are available aside from 32bit 1080p? Any acceleration?

@balaton

Understood - it's not a big problem for what I'm doing with OS4 at the moment. I can experiment to see if any other kinds of card work better for me. I also like the idea of looking at a driver.

Unfortunately that's not 100% the case because I'm already doing that.

Just so you know how I'm running on my Mac Mini (M1)

@balaton

You read my mind somewhat on the networking! So when I say it's problematic, the RTL device will just stop working randomly. I noted from your web page that after the OS updates you may need to downgrade back to the version on the CD but it still does it. I used bridged mode by running qemu as root. I've built Qemu from source so I'm running on master, though I'm guessing that doesn't make a huge difference.

My NAS at home has a bridged interface which was doing a good job of upsetting OS4 (Roadshow?) because the MAC address would randomnly flick between the two ports on the interface. I changed that bridge to just be in standby / failover mode instead and I haven't checked to see if that has helped. I could certainly see it being problematic if it decided to switch half way through a big transfer. If that's even something that it would do.

I did also spend time reading through various documentation and notes, some of which may well have been from you (what you said sounds familiar) and I have to say, it didn't all fly miles over my head and I did end up thinking I could possibly take a look. That was probably a week or two back? I haven't ruled out looking into it. From memory I think I forumlated a plan in my head to see if I could implement some sort of stub driver that at least spits out some logging and if I get that far go from there.

Apologies if this is de-railing the main topic here!

@geennaam
Sure, I'm aware. I already have OS4 fully up and running in Qemu using SM501 on a spare disk in my gaming PC and on my day-to-day Mac Mini. It runs very well mostly, better than under WinUAE or FS-UAE, but of course it runs like a snail, or not at all as soon as you hit it with something that needs real GPU capabilities.

I am indeed debating whether to follow along and experiment with GPU passthrough. When I first got my current gaming PC a few years back that's how I had it, a very slim linux boot and then either Windows or Linux via virtIO. The motherboard is extremely good at segmenting all the bits and allowing passthrough. Right now it's not setup that way.

@geennaam

Thanks - for now I only have OS4 CDs for classic and Pegasos2.

I'm wondering if I should try to find a second hand card and likely a bridge card as well since my PC only has PCIe. I do have an older motherboard that is I think has an i7 6700k in it. That has a PCI slot but it probably getting a bit slow and I'd have no idea if it supports pass-through. It certainly predates it being popular that's for sure.

Which graphics cards are relevant here? I'm assuming if we're doing passthrough then it has to be something that OS4 natively supports? The only spare card I have, IF I can get hold of a power cable for it (thats the whole reason it's spare, I've lost it in a house move) is a Sapphire RX580 which I assume is far too modern?

I just wanted to post and say that I registered here since I'm following this thread with great interest. I have been "using" OS4.1FE very occasionally since it was released for classic but I've never *really* used it since graphics support was always an issue. Just recently I became aware of the Pegasos2 / Qemu situation so I bought OS4.1 again and set that up. It's really very nice now on my M1 Mac but clearly still fails to deliver in the GPU department (and networking as it goes).

I am a developer of over 30 years for a living but I have zero knowledge of drivers so I very much fit into the category of "willing to learn", but I don't think having a complete noob sticking their nose in blindly asking a thousand questions would be remotely helpful right now. Please say if that's not the case or there is anything that you think could be helped with, otherwise I'll just go back to "lurking with interest".

I am toying with the idea of buying 4.1 hardware at the moment but obviously that is a big investment.

Anyway,