"Brian S. Julin" wrote: > > On Fri, 20 Apr 2001, Sven Garbade wrote: > > oh, were can I get the sources? Sorry, but I haven't found them on > > www.ggi-project.org. And another question: is it possible to sync a ggi > > application with the vertical retrace? I've tried several ways with > > medium success (e.g. using SDL and reading the VGA vrt bit). > > LibGGIMisc (the one in the GGI snapshots right now) will > support vrt sync on the svgalib target. It basically just > does the same thing, though. The problem with SDL is, that you have to call a special update function to update the changed areas on screen. This function doesn't care about "self-designed" vrt functions, nevertheless, you get better results. > I have a new proposed version of LibGGIMisc released, and another one > to follow (the next release will require LibGalloc). I would > expect that that will be ready for production use in about a month. > That version adds vrt sync using the fbdev target, which will use > the more advanced chipset-specific registers. However the only > fbdev driver in the kernel that actually implements vrt is matroxfb, > so unless you want to add that function to the fbdev driver for > your chipset, it won't be useful. I´ve got a Matrox G400, so matroxfb should work. > I also have some code where I have been playing around with the > standard VGA VRT bits and the pentium-class rdtsc assembler instruction, > to try to figure out where the raster beam is just by reading the > processor time-stamp counter, which does not require any special > access privilages or bus IO. If you are into kernel hacking, then > I can send you that code (will need updating for 2.4, last time it > was updated was late 2.2/early 2.3) It is kind of flaky right > now, as I need a better algorithm to quickly calibrate the equation > for finding the relationship between the retrace and the time-stamp > counter. Actually I'm still using kernel 2.2.18 (with RTAI-Linux). It would be nice, if you can send me the code. Many Thanks, Sven
