[PATCH libdrm] libdrm: Allow dynamic drm majors on linux

[Emil Velikov]

Hi Thomas,

On 31 August 2018 at 12:54, Thomas Hellstrom <thellstrom at vmware.com> wrote:
> To determine whether a device node is a drm device node or not, the code
> currently compares the node's major number to the static drm major device
> number.
>
> This breaks the standalone vmwgfx driver on XWayland dri clients,
> https://cgit.freedesktop.org/mesa/vmwgfx

Any particular reason why the code doesn't use a fixed node there?
It will make the diff vs the in-kernel driver a bit smaller.

> and any future attempt to introduce dynamic device numbers for drm.
>
I'm not sure how well any such attempt will pan out, regardless of the
libdrm checks.

Namely: the static 226 has been used by a number of tools that
interpose the libc' ioctl function.
There could be others that also depend on it.

Personally, I'd go with the kernel developers decision.

Dave, Daniel, others
Should we keep or drop the major == 226 checks.

Thanks
Emil