Most cards are not programmed via vga IO ports anymore. They are programmed via memory mapped registers and there is not a standard for this. They are different for every vendor. Mark. On Sun, 15 Feb 2004, Jihong Ren wrote: > Hi, > > I am trying to synchronize several graphics cards on the same machine. > I would like to be able to read the current status of each individual > graphics > card, whether they are currently in retrace or not, and also how to > read/write the registers on each graphics card that store hsync/vsync > values. There are literature on vga programming which does about the same > job except that they are on a single graphics card. For example, simply > reading the port 3dah tells whether the screen is being traced. However, > I guess this only works for one graphics card. > > I guess for multihead display, one of the cards is still using the normal > vga ports: 03c0 - 03df. > Registers for other cards are rellocated somewhere else. Anyway to find > out? > I don't have much experience in this area. Your help is really > appreciated. > > Thanks in advance. > > Jihong > _______________________________________________ > XFree86 mailing list > XFree86@xxxxxxxxxxx > http://XFree86.Org/mailman/listinfo/xfree86 > _______________________________________________ XFree86 mailing list XFree86@xxxxxxxxxxx http://XFree86.Org/mailman/listinfo/xfree86
