PS(4) BSD/vax Kernel Interfaces Manual PS(4)NAMEps — Evans and Sutherland Picture System 2 graphics device interface
device ps0 at uba? csr 0172460 vector psclockintr pssystemintr
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
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 fol‐
lowing 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
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
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.
DIAGNOSTICSps device intr.
ps dma intr. An interrupt was received from the device. This shouldn't
happen, check your device configuration for overlapping interrupt vec‐
The ps driver appeared in 4.2BSD.
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 4.2 Berkeley Distribution