NAME

bwtwo − black and white memory frame buffer

CONFIG SOLBOURNE SERIES 4, 5, 5E, 6

device bwtwo0 at kbslot ? csr 0x00200000 priority 4

CONFIG SOLBOURNE S4000, S3000

device bwtwo0 at obio ? csr 00001000 priority 6
device bwtwo1 at obio ? csr 00001000 priority 6
device bwtwo2 at obio ? csr 00001000 priority 6

DESCRIPTION

The bwtwo interface provides access to Solbourne 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.  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] device files

SEE ALSO

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

BUGS

Use of vertical-retrace interrupts is not supported. 

Solbourne Computer, Inc.  —  10 Nov 1992