For anyone else as uninitiated as me:

> Generic Buffer Management (GBM) is an API that provides a mechanism for allocating buffers for graphics rendering tied to Mesa. GBM is intended to be used as a native platform for EGL on DRM or openwfd. The handle it creates can be used to initialize EGL and to create render target buffers.

Where

> The Direct Rendering Manager (DRM) is a subsystem of the Linux kernel responsible for interfacing with GPUs of modern video cards. DRM exposes an API that user-space programs can use to send commands and data to the GPU

https://en.wikipedia.org/wiki/Mesa_(computer_graphics)#Gener... and https://en.wikipedia.org/wiki/Direct_Rendering_Manager

What does it mean for nvidia to jump on the GBM bandwagon? Firefox would just talk (perhaps via some intermediate API like EGL or BGM) to the Linux kernel for talking to an nvidia card, if I understand it correctly?

With the proprietary driver, the GPU is controlled by their closed-source kernel module, so Mesa's GBM code wouldn't know how to talk to it. However, as of the latest version, NVIDIA is shipping a GBM back-end library that Mesa can load which is able to talk to their module.

I wonder if nvidia will ever integrate into the kernel properly. Using their drivers is such a poor user experience.

So Firefox, not using GBM but EGL, would not be able to make use of the proprietary driver and has to talk to DRM? Can two kernel modules even use the same card at the same time?

> Can two kernel modules even use the same card at the same time?

yes, I'm not sure how everything is divvied up. NVIDIA ships multiple kernel modules in their driver, and one of them is called ‘nvidia_drm’. So idk, maybe you have to use their DRM implementation or something

But what does this mean for applications that use Vulkan?

Probably nothing, similar for most applications using EGL it doesn't mean much.

But it does matter for developers of Wayland compositors. A lot.

It would mean that desktop compositors do no longer need to have two implementations for a lot of parts.

This e.g. mean developer cost for gnome/kde would be reduced and sway(wlroots) would work on devices with Nvidia cards (at least some).

I.e. in general it makes it easier for everyone, except maybe Nvidea. But even for them it (long term) could make maintenance simpler.

Yes, the latest stable version 495 has GBM support.