IK(4) | Device Drivers Manual (vax) | IK(4) |
ik
—
ik0 at uba? csr 0172460 vector ikintr
The ik
driver 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, via virtual memory, into the user processes address space. This
allows the user process very high bandwidth to the frame buffer with no
system call overhead.
Bytes written or read from the device are DMA'ed from or to the interface. 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 via ioctls. The
IK_GETADDR
ioctl(2) returns the virtual
address where the user process can find the interface registers. The
IK_WAITINT
ioctl(2) suspends the user
process until the ikonas device has interrupted (for whatever reason
— the user process has to set the interrupt enables).
ik
driver appeared in
4.2BSD.
June 5, 1993 | NetBSD 9.4 |