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. 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 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. -- Brian
