IK(4) NetBSD Programmer's Manual (VAX Architecture) IK(4) NNAAMMEE iikk - Ikonas frame buffer, graphics device interface SSYYNNOOPPSSIISS ddeevviiccee iikk00 aatt uubbaa?? ccssrr 00117722446600 vveeccttoorr iikkiinnttrr DDEESSCCRRIIPPTTIIOONN The iikk 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 virtu- al memory, into the user processes address space. This allows the user process very high bandwidth to the frame buffer with no system call over- head. Bytes written or read from the device are DMA'ed 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 via ioctls. The IK_GETADDR ioctl(2) returns the virtual address where the user process can find the interface registers. The IK_WAITINT ioctl suspends the user process un- til the ikonas device has interrupted (for whatever reason -- the user process has to set the interrupt enables). FFIILLEESS /dev/ik DDIIAAGGNNOOSSTTIICCSS None. HHIISSTTOORRYY The iikk driver appeared in 4.2BSD. BBUUGGSS An invalid access (e.g., longword) to a mapped interface register can cause the system to crash with a machine check. A user process could possibly cause infinite interrupts hence bringing things to a crawl. 4.2 Berkeley Distribution June 5, 1993 1