BWTWO(4S)

NAME
bwtwo - black and white memory frame buffer

CONFIG — SUN-3, SUN-3x SYSTEMS
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
device bwtwo0 at obmem ? csr 0x50300000 priority 4

The first synopsis line given above is used to generate a kernel for Sun-3/75, Sun-3/140 or Sun-3/160 systems; the second, for a Sun-3/50 system; the third, for a Sun-3/260 system; the fourth, for a Sun-3/110 system; the fifth, for a Sun-3/60 system; and the sixth for Sun-3/80 and Sun-3/470 systems.

CONFIG — SUN-4 SYSTEMS
device bwtwo0 at obio 1 csr 0xfd000000 priority 4
device bwtwo0 at obio 2 csr 0xfb300000 priority 4
device bwtwo0 at obio 3 csr 0xfb300000 priority 4
device bwtwo0 at obio 4 csr 0xfb300000 priority 4

The first synopsis line given above should be used to generate a kernel for a Sun-4/260 or Sun-4/280 system; the second, for a Sun-4/110 system; the third for a Sun-4/330 system; and the fourth for a Sun-4/460 system.

CONFIG — SUN-4c, SUN-4m SYSTEMS
device-driver bwtwo

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-3/75, Sun-3/140, 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]
    device files

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

BUGS
Use of vertical-retrace interrupts is not supported.