[PATCH] drm: support up to 128 drm devices

[Simon Ser]

On Monday, July 17th, 2023 at 09:30, Emil Velikov <emil.l.velikov at gmail.com> wrote:

> > I'm worried what might happen with old user-space, especially old libdrm.
> 
> I also share the same concern. Although the bigger issue is not libdrm
> - since we can update it and prod distributions to update it.
> The biggest concern is software that cannot be rebuild/updated -
> closed source and various open-source that has been abandoned.

Well. Now that we have Flatpak and AppImage and friends, we're really likely
to have old libdrm copies vendored all over the place, and these will stick
around essentially forever.

> For going forward, here is one way we can shave this yak:
>  - update libdrm to max 64 nodes
>  - roll libdrm release, nag distributions to update to it // could be
> folded with the next release below
>  - update libdrm to use name driven type detection
>  - roll libdrm release, nag distributions to update to it
>  - once ^^ release hits most distributions, merge the above proposed
> kernel patch
>    - the commit message should explain the caveats and fixed libdrm version
>    - we should be prepared to revert the commit, if it causes user
> space regression - fix (see below) and re-introduce the kernel patch
> 1-2 releases later

That sounds really scary to me. I'd really prefer to try not to break the
kernel uAPI here.

The kernel rule is "do not break user-space".