ik(4) Unsupported ik(4)Nameik - Ikonas frame buffer, graphics device interface
device ik0 at uba? csr 0172460 vector ikintr
The program provides an interface to an Ikonas frame buffer graphics
device. Each minor device is a different frame buffer interface board.
When the device is opened, its interface registers are mapped, by vir‐
tual memory, into the user processes address space. This allows the
user process very high bandwidth to the frame buffer with no system
Bytes written or read from the device are DMA'd from or to the inter‐
face. The frame buffer XY address, its addressing mode, etc. must be
set up by the user process before calling write or read.
Other communication with the driver is by ioctls. The IK_GETADDR ioctl
returns the virtual address where the user process can find the inter‐
face registers. The IK_WAITINT ioctl suspends the user process until
the ikonas device has interrupted (for whatever reason — the user
process has to set the interrupt enables).
An invalid access (for example, longword) to a mapped interface regis‐
ter can cause the system to crash with a machine check.