Subject: Aperture driver for XFree86
To: None <>
From: Matthieu Herrb <>
List: current-users
Date: 07/03/1994 18:01:35

I've placed a new version of my aperture driver for XFree86 on

In order not to break the kernel security too much,I've made the
following modifications:

1. Only one open() of /dev/xf86 is allowed at a time. So once you've
   lauched X, (which keeps it open) no other process can access it.
   If you're really concerned about kernel security, you can start xdm
   at boot time.

2. Only mapping of the VGA frambuffer (0xA000-0xBFFFF - as in
   /dev/vga) and of physical adresses above physmem are allowed. I
   cannot restrict that more, because there aren't two VLB VGA board
   with same addressing decoding method. So XFree86 is peeking around
   to find the adress of the framebuffer at startup time.

   If you know the physical address of your particular card, you can
   use the 'memebase' directive in Xconfig to disable the probe and
   recompile the aperture driver with *your* values.

And I remind you that only root is allowed to open /dev/xf86 and that
only mmap() is implemented aprt of open() and close().

For now it's still a loadable kernel module, but I'm open to integrate
it in the kernel if you find it worth. (It could for example be merged
with pccons's mapping of /dev/vga).

I've given this version to the XFree86 Dev. Team for inclusion in

By the way, there will be kind of a race between the release of
XFree86 3.1 and NetBSD 1.0. I hope that there won't be too much
new changes affecting X support so that XFree86 3.1 can support
NetBSD 1.0.