Chris Gray asked;

> More particularly is there a general way to port sw which uses Linux 
> /dev/fb to netbsd? 

I start recognizing that there has been a large influx into MIPS from off-RISC
world :-)

I have little knowledge about Linux /dev/fb and the software you mentioned, 
however, if your target software just wants to render bitmaps on bare framebuffer,
it's the answer to mmap framebuffer into application address space like as;

    fd = open("/dev/ttyE0", 2);

    ioctl(fd, WSDISPLAYIO_GTYPE, &rv); 
    /* To see the hardware is one you wants */
    
    ioctl(fd, WSDISPLAYIO_GINFO, &fbi);
    /* To determine framebuffer dimension */

    rv = WSDISPLAYIO_MODE_MAPPED;
    ioctl(ws, WSDISPLAYIO_SMODE, &rv);
    /* To tell WSCONS mode switch will follow */

    ptr = mmap(0, mapsize, PROT_READ|PROT_WRITE, MAP_PRIVATE, ws, mapoff);
    /* mapsize and mapoff are target hardware dependent */

ptr would be the start address of linear framebuffer memory, or start address of display
controlling hardware registers if wscons driver layouts so.  Beware, please.  I have been
talking in linear framebuffer context and never in VGA/VEGA context.

Toru Nishimura/ALKYL Technology

I would like to point out the mmap scheme mentioned was the sun2/SunOS invention of
1980's, not by Linux.