To make sure X support is enabled under OpenBSD, the following
line must be in your config file in /sys/arch/i386/conf:
option XSERVER
option APERTURE
The server supports the two standard OpenBSD/i386 console drivers: pcvt and pccons. They are detected at runtime and no configuration of the server itself is required.
The pcvt console driver is the default in OpenBSD. It offers several virtual consoles and international keyboard support.
By default OpenBSD includes the BSD 4.4 kernel security
feature that disable access to the /dev/mem device when in
multi-users mode. But the XFree86 server require
linear access to the display memory in most cases.
OpenBSD now requires the aperture driver to be enabled for all X servers, because the aperture driver also controls access to the I/O ports of the video boards.
To enable the aperture driver, once included in the kernel, set
machdep.allowaperture=1
/etc/sysctl.conf.
Another (less recommended) way to enable linear memory and I/O ports
access is to disable the kernel security feature by adding ``option
INSECURE'' in your kernel configuration file and build a new kernel.
You will also need to comment out the line
initializing securelevel to 1 in /etc/rc.securelevel.
Caveat: the aperture driver only allows one access at a time (so that the system is in the same security state once X is launched). This means that if you run multiple servers on multiples VT, only the first one will have linear memory access. Use 'option INSECURE' if you need more that one X server at a time.
OpenBSD supports System V shared memory. If XFree86 detects this support in your kernel, it will support the MIT-SHM extension.
To add support for system V shared memory to your kernel add the lines:
# System V-like IPC
options SYSVMSG
options SYSVSEM
options SYSVSHM
to your kernel config file.