GSdx Memory Coherency

[dabore]

What path...? ... at the top.

GSgifTransferX(...) ... happy debugging.

[keldor314]

Ok, it looks like the most sensible place to check for updates would be in the DMAC stage, where everything is properly synchronized. Unfortunately, there seems to be no documentation on how the emulator handles DMAC. There's a nice dev blog post describing how DMAC works on the PS2 hardware, which promises a followup post on how PCSX2 works that has been less forthcoming than the first.

A few important questions:

1. Is the memory allocated in WinHostSys.cpp the same as that used directly by the EE? I need to know if there are any copies going on whatsoever, since the writewatch has to be on the right buffer.

2. What's the thread safety picture from DMAC through Draw? Specifically, is it possible that the EE might overwrite a texture before it goes into the texture cache?

3. What's the call sequence between the DMAC stage and the actual call to draw?

4. Is there any possible path for the DMAC to force update the texture cache directly? That would bypass any threading issues nicely.

5. Do we have any sort of call graph floating around somewhere???