Copyright (c) 1983 Regents of the University of California.
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@(#)ps.4 6.1 (Berkeley) 05/15/85

C 5 ps - Evans and Sutherland Picture System 2 graphics device interface "device ps0 at uba? csr 0172460 vector psintr" 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 ioctls:

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 thru these refresh buffers displaying them one by one on the screen.

PSIOAUTOMAP

Start automatically passing the display file thru 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 thru 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.

/dev/ps "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.

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.