NAME

bwtwo − Sun-3/Sun-2 black and white frame buffer

CONFIG — SUN-3 SYSTEM

device bwtwo0 at obmem 1 csr 0xff000000 priority 4
device bwtwo0 at obmem 2 csr 0x100000 priority 4
device bwtwo0 at obmem 3 csr 0xff000000 priority 4
device bwtwo0 at obmem 4 csr 0xff000000
device bwtwo0 at obmem 7 csr 0xff000000 priority 4

The first synopsis line given above should be used to generate a kernel for a Sun-3/75, Sun-3/140 or Sun-3/160 system; the second, for a Sun-3/50 system; the third, for a Sun-3/260 system; the fourth, for a Sun-3/110 system; and the fifth, for a Sun-3/60 system. 

CONFIG — SUN-2 SYSTEM

device bwtwo0 at obmem 1 csr 0x700000 priority 4
device bwtwo0 at obio 2 csr 0x0 priority 4

The first synopsis line given above should be used to generate a kernel for a Sun-2/120 or Sun-2/170 system; the second, for a Sun-2/50 or Sun-2/160 system. 

CONFIG — Sun386i SYSTEM

device bwtwo0 at obmem ? csr 0xA0200000

DESCRIPTION

The bwtwo interface provides access to Sun monochrome memory frame buffers.  It supports the ioctls described in fbio(4S). 

If flags 0x1 is specified, frame buffer write operations are buffered through regular high-speed RAM.  This “copy memory” mode of operation speeds frame buffer accesses, but consumes an extra 128K bytes of memory.  Only Sun-2, Sun-3/75, and Sun-3/160 systems support copy memory; on other systems a warning message is printed and the flag is ignored. 

Reading or writing to the frame buffer is not allowed — you must use the mmap(2) system call to map the board into your address space. 

FILES

/dev/bwtwo[0-9]

SEE ALSO

mmap(2), cgfour(4S), fb(4S), fbio(4S)

BUGS

Use of vertical-retrace interrupts is not supported. 

Sun Release 4.0  —  Last change: 18 February 1988