Linus Torvalds wrote: > > On Fri, 14 Jun 2002, Jos� Fonseca wrote: > >>So to avoid being constantly checking for conclusion before asking to >>process new entries we devised a different scheme: >> >> - after adding new entries to the ring >> >> - toggle the end flag of the previous last entry, so that the engine >>will also process our just commited buffers >> > > If this is in non-coherent memory (AGP), I hope you do an "sfence" in > between those two stages? You also need to make sure that the compiler > hasn't re-ordered them (ie a compiler barrier() in between), regardless of > memory ordering. > > I also hope you do the toggle with a locked cycle so that you don't lose > any information..
Is this necessary if the toggle is really just a write? Jose, you're not doing a read-modify-write operation on that flag are you? I suppose to some extent we're relying on the atomicity of the mach64's use of that flag as well -- I don't know if there are any obvious ways they could get it wrong (I assume they just fetch it once...) -- so that's probably not a huge problem. Keith _______________________________________________________________ Don't miss the 2002 Sprint PCS Application Developer's Conference August 25-28 in Las Vegas - http://devcon.sprintpcs.com/adp/index.cfm?source=osdntextlink _______________________________________________ Dri-devel mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/dri-devel
