Hi, Alex Villacís Lasso escreveu: > Another question I have is this: as far as I understand, PCI video cards > have to run the POST (or do an equivalent operation) in order to execute > the chipset-specific hocus-pocus that enables legacy vga port access > (0x3c0 through 0x3df). So only one chipset can be mapped into that I/O > address range at a time (right?).
right. Note that some modern video cards can entirely scape from this legacy VGA crappy. > When initializing a secondary card via > POST, the real-mode code of the secondary card will also attempt to map > its own registers into that range (I would assume). So what steps are > taken in the xserver to move the primary card out of the way (if at all) > so that the second card initializes properly? What happens if the > drivers for both chipsets require some access to the legacy I/O ports in > order to perform normal operations? this is currently addressed by the RAC module inside the Xorg server. But this module is selfish and only provides informations to its X server. If you have two or more applications (e.g. X servers) trying to use the VGA registers then the machine will probably hang (maybe not hang, but you will see a lot of crazy things on screen... like the lights of a rave party, or a screen that remembers an Atari game... well, it will depends in the kind of things you'll be smoking). Cheers, -- Tiago Vignatti C3SL - Centro de Computação Científica e Software Livre www.c3sl.ufpr.br _______________________________________________ xorg mailing list xorg@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/xorg