[Feature Request] Vulkan support in Bumblebee/Primus

[edoantonioco]

Hello, I have tried with windows vulkan demos (on wine staging), the talos principle (which on the logs says than it use the intel card even if I use primusrun, only when trying to run it with the vulkan renderer), and the vulkan caps viewer (which can only sees the intel gpu even if I use primusrun), and it does not work, because when I try "primusrun randomVulkanApp' (for example), it never use the nvidia card, it uses the intel card.

My hardware is intel haswell, nvidia 960m, driver 364.19, Manjaro

[ArchangeGabriel]

Yes, that’s expected. We don’t support Vulkan at all currently, and it’s probably not going to happen any time soon. I’m wondering what’s the status of PRIME on this thought. Is there any native Linux Vulkan demo thing that reports the used card for me to test that?

[edoantonioco]

This is a shame, because for what I have seen PRIME is a technology than its meant mainly for ubuntu-based distros, and I guess than I could modify the Xorg.conf to only use the nvidia card, but on a laptop I also want to use the intel card.
Anyway, I havent found a vulkan demo easy to install without having to compile and etc, but if you want a software than tell you what card you are using, I found two ways, 1st is the talos principle, on the log it will tell you. 2nd, the vulkan hardware capability viewer, on the GUI appears which card it is detecting.
I hope than support for this new API will happen soon

[ArchangeGabriel]

I think you’re confused about PRIME. What you cite is Nvidia reverse PRIME. But PRIME is way more than that (take a look at default PRIME function: https://wiki.archlinux.org/index.php/PRIME#PRIME_GPU_offloading).

However, after sleeping a bit, I found the answer by myself: Vulkan won’t work with PRIME currently, at least because they are no Vulkan driver in Mesa at all (and the only one that is coming for sure is Intel, which AFAIU we don’t need here). Nevertheless, it might work in reverse PRIME indeed. But that’s not ideal, granted.

For our purpose, it would take someone adding Vulkan support in Primus just like OpenGL is supported right now. I’m not sure anyone having this capacity is willing to spend time on this, especially given that in the individuals around this project I count at most 2 that could: @karolherbst, but he is busy developing nouveau — which is a far greater priority — and has already stated that he won’t maintain Primus ; a discussion that happened because the other one people I think of, @amonakov, actual Primus dev and maintainer, is almost MIA.

So, I’m sorry about this (not just for you, I would love to see that too), but unless you manage to find someone who can and want to implement this, nothing is going to happen here.

[karolherbst]

@ArchangeGabriel there is an intal vulkan driver already, but I thought that offloading on other GPUs is already builtin into vulkan?

Well, if not, then they always forget the important bits

[ArchangeGabriel]

I know about the Intel driver (first parenthesis in my previous message), but I thought that like in OpenGL case, we don’t care about the Intel part, only Nvidia side. However, you might well be right about offloading, I remember having read something about this and the ability to use very heterogeneous setups in terms of graphic cards. Which probably requires Vulkan on both sides.

So, in the end, if that’s right, maybe we could do something in Bumblebee for Vulkan support (it probably comes down to the --no-xorg option in fact, ensuring driver loading and paths setting, or a modification of it to take Vulkan into account).

[bluca]

Something else to keep an eye on is libglvnd: https://github.com/NVIDIA/libglvnd
Upstream's NVIDIA driver already uses it (coming in Debian as soon as the new versions clear the NEW queue), and work is going on to have Mesa use it.
Once they both do, it might be an alternative to Primus, maybe?

[Amanieu]

Some quick experiments when running vulkaninfo under optirun (I am using the proprietary drivers):

• optirun vulkaninfo will only recognize the Intel GPU.
• DISPLAY=:8 optirun vulkaninfo will recognize both the Intel and Nvidia GPUs.

So it seems that Nvidia's vulkan driver only works if DISPLAY points to an X server running on the Nvidia GPU. Of course this isn't very useful for my laptop since that X server isn't connected to a screen, and no windows appear for graphical applications.

[karolherbst]

@Amanieu that is most likely the case because nvidia isn't loaded and the GPU is off.

What is the output of optirun -b none vulkaninfo?