On Wed, 24 Apr 2002, Frank C. Earl wrote: > On Wednesday 24 April 2002 06:15 am, you wrote: > > Hi, there! > > > For enabling DMA on Mach64 I'll need to allocate two extra DMA buffers: a > > primary DMA buffer and a decription table buffer. > > All you need for now is a descriptor table. The buffers that you have > already allocated via the DRM's framework should be allocated page aligned > and you'll have the bus address in hand. The only reason you'd need a > "primary" buffer is if you had an engine that wasn't at all secure (The > RagePRO's pretty much secure, it won't let you set up DMA sessions, etc. and > you can undo anything that might cause confusion in the engine at the end of > the pass (Use the Utah-GLX code for the closeout of a DMA pass for a hint > there...).) and you're "securing" the vertex path.
I know you need to flag the final descriptor at the end of the pass by setting END_OF_LIST_STATUS in BM_COMMAND (third dword of the descriptor). In Utah-glx, there's also a series of register writes added to end of the buffer to "go back to drawing on the front buffer the way the X server expects." Is this necessary? Utah-glx does this even for pseudo-DMA, but we don't do this currently. > For now, I'd be seeing what you can do to just get it going. All you > need is a descriptor table at that point. Use the memory pool api to > allocate that one just like in the BUS-Master test. I was starting to try setting up the descriptor table through the DRM framework as well, but I'm thinking that this might be the best way to get started. > At that point, we'll have a DMA system (Though it ties up > the framework for any given pass- the code I'm completing happens to have a > full-blown queue, etc that is governed by the CTRC interrupt.). It may not > be quite what I have in hand, but as Gareth has said before, get it working- > I'm just waay to busy to have completed what I had in mind up until recently. > -- Leif Delgass http://www.retinalburn.net _______________________________________________ Dri-devel mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/dri-devel
