Timothy Normand Miller wrote: > But I also would like to see an analysis that suggests something will > be terribly hurt by us having slow performance in VGA mode. > > My underlying concern is that regardless of how much we may wish VGA compatibility didn't exist, not only does it have to, it will be the first thing a "user" sees when using an open graphics based card on an x86 system. The last thing we want it for the first impression to be "Boy this sucks..."
We certainly need to have a reasonable update rate in both text and graphics VGA mode since x86 systems will use these modes during OS installs. Whether we like it or not, the VGA interface will be the first experience with an open graphics based card for the majority of the end users. > >> call. This means that if we miss a PCI read transaction, we still have >> to get the data if possible. This could cause problems if we have other >> queue memory requests unless we have separate memory pipelines for PCI >> and VGA nanocontroller memory requests. We have to be able to determine >> whether a data value coming from a memory read is for a prior request by >> the VGA code or by the PCI code. >> > > My suggestion is to check for PCI requests only at those points where > we have no pending requests. We can check for a significant number of > them. We can do that between every pair of characters when > translating 80x25. Then between frames, we can poll a few thousand > times before going to the next. > > > Hmmm. I think I have missed something somewhere. What exactly does the nano controller have to handle during a PCI transaction? _______________________________________________ Open-graphics mailing list [email protected] http://lists.duskglow.com/mailman/listinfo/open-graphics List service provided by Duskglow Consulting, LLC (www.duskglow.com)
