ps
—
Evans and Sutherland Picture System 2 graphics device
interface
ps0 at uba? csr 0172460 vector psclockintr pssystemintr
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.
- 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.
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.