PS(4)

NAME
ps - Evans and Sutherland Picture System 2 graphics device interface

SYNOPSIS
ps0 at uba? csr 0172460 vector psclockintr pssystemintr

DESCRIPTION
NOTE: This driver has not been ported from 4.4BSD yet.

The ps driver provides access to an Evans and Sutherland Picture System 2 graphics device. Each minor device is a new PS2. When the device is opened, its interface registers are mapped, via virtual memory, into a user process's address space. This allows the user process very high bandwidth to the device with no system call overhead.

DMA to and from the PS2 is not supported. All read and write system calls will fail. All data is moved to and from the PS2 via programmed I/O using the device's interface registers.

Commands are fed to and from the driver using the following ioctl(2)s:

PSIOGETADDR
    Returns the virtual address through which the user process can access the device's interface registers.

PSIOAUTOREFRESH
    Start auto refreshing the screen. The argument is an address in user space where the following data resides. The first longword is a count of the number of static refresh buffers. The next count longwords are the addresses in refresh memory where the refresh buffers lie. The driver will cycle through these refresh buffers displaying them one by one on the screen.

PSIOAUTOMAP
    Start automatically passing the display file through the matrix processor and into the refresh buffer. The argument is an address in user memory where the following data resides. The first longword is a count of the number of display files to operate on. The next count longwords are the address of these display files. The final longword is the address in refresh buffer memory where transformed coordinates are to be placed if the driver is not in double buffer mode (see below).

PSIODOUBLEBUFFER
    Cause the driver to double buffer the output from the map that is going to the refresh buffer. The argument is again a user space address where the real arguments are stored. The first argument is the starting address of refresh memory where the two double buffers are located. The second argument is the length of each double buffer. The refresh mechanism displays the current double buffer, in addition to its static refresh lists, when in double buffer mode.

PSIOSINGLEREFRESH
    Single step the refresh process. That is, the driver does not continually refresh the screen.

PSIOSINGLEMAP
    Single step the matrix process. The driver does not automatically feed display files through the matrix unit.

PSIOSINGLEBUFFER
    Turn off double buffering.

PSIOTIMEREFRESH
    The argument is a count of the number of refresh interrupts to take before turning off the screen. This is used to do time exposures.

PSIOWAITREFRESH
    Suspend the user process until a refresh interrupt has occurred. If in TIMEREFRESH mode, suspend until count refreshes have occurred.

PSIOSTOPREFRESH
    Wait for the next refresh, stop all refreshes, and then return to user process.

PSIOWAITMAP
    Wait until a map done interrupt has occurred.

PSIOSTOPMAP
    Wait for a map done interrupt, do not restart the map, and then return to the user.

FILES

/dev/ps

DIAGNOSTICS

ps device intr.

ps DMA intr. An interrupt was received from the device. This shouldn't happen, check your device configuration for overlapping interrupt vectors.

HISTORY
The ps driver appeared in 4.2BSD.

BUGS
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.