On Mon, Dec 11, 2000 at 06:26:51PM -0800, Jun Sun wrote: > Guido Guenther wrote: > > > > On Mon, Dec 11, 2000 at 12:28:19PM +0100, Maciej W. Rozycki wrote: > > > friends) by glibc. At least XFree86 and SVGATextMode make use of these > > > features. I suppose it's the same for MIPS (I haven't checked, though). > > Yes. xf86MapVidMem & friends use /dev/mem to mmap videomemory & iospace > > independent of architecure. > > -- Guido > > > I am surprised. I thought /dev/mem is for accessing SYSTEM RAM. (do a 'man' I'd not call it system ram but rather ''visible address space'' or something. If there's actually ''system ram'' or the fb of a graphics card at a given address doesn't make a difference. > on /dev/mem) It is also confirmed by the code in drivers/char/mem.c. If you > want to access anything beyond 'high_memory", nothing is read. > > Note that drivers/char/mem.c is cross-platform code. I am not sure how X > would access video memory through /dev/mem on either MIPS or other platforms. The newports REX3 for example is at (KSEG1 + 0x1f0f000) which is mmaped by the xserver to access the REX3s registers. -- Guido
