On Tue, 22 Jun 2004, Andrzej Popielewicz wrote: > >>I am porting one of the older releases of XFree, namely 2.1. > >That's pretty old. > >>Simple question : what is the meaning of VGABASE (defined as 0xf0000000 > >>or 0xff000000 depending on OS). > >>vgaBase is the virtual address of memory mapped to VGA 0xa0000. > >>vgaVirtBase is set to VGABASE for SVGA server (and to vgaBase for mono > >>nonbanked) .Or in other words : how to set vgaVirtBase for SVGA ? > >VGABASE is a value used to distinguish between banked framebuffer data, and > >non-banked framebuffer data (or pixmap data). > Are You sure ? > VGABASE is used(in banked case) in different vgaSetReadWrite etc > routines(usually in assembler) , in order to set the corresponding bank > for given buffer pointer. It is treated as usual address(pointer)(?). > Or You simply mean the same ? > The question is not what VGABASE is good for, but why it is set to > 0xf0000000 . VGABASE is a value that should never occur for a real framebuffer, banked or otherwise. I'll grant that VGABASE could have been set to the same value regardless of OS/architecture, and it was at one time. Over time, it was changed only for those situations where the original value isn't suitable, and it wasn't globally changed to prevent breaking what was already working. Marc. +----------------------------------+-----------------------------------+ | Marc Aurele La France | work: 1-780-492-9310 | | Computing and Network Services | fax: 1-780-492-1729 | | 352 General Services Building | email: tsi@xxxxxxxxxxx | | University of Alberta +-----------------------------------+ | Edmonton, Alberta | | | T6G 2H1 | Standard disclaimers apply | | CANADA | | +----------------------------------+-----------------------------------+ XFree86 developer and VP. ATI driver and X server internals. _______________________________________________ XFree86 mailing list XFree86@xxxxxxxxxxx http://XFree86.Org/mailman/listinfo/xfree86
