> > > For a bt848, when are the risc program(s) generated? When REQBUFS is called, > > > or when VIDIOC_QBUF is called? > > > > QBUF. > > Isn't that inefficient? Last time I checked, risc program generation takes > a significant length of time. Depends. Generating the risc code at REQBUFS time means that you'll limited to a fixed set of buffers. Depending on your application it might save you a memcopy() if you can put it _anywhere_ and not only to one of the predefined buffers. BTW: This is how bttv works today. It will write new risc code for every single frame you are capturing. So it can't be that slow as you can capture full frame rate and have (on fast boxen) still enouth spare CPU time to compress the video in real time... For the case the applications wants reuse the buffers I suggest the hint flag mentioned in the last mail -- so the driver knows it is worth keeping the risc code for that buffer (and also keep the memory locked down to make sure the risc code hasn't outdated addresses). Gerd -- Get back there in front of the computer NOW. Christmas can wait. -- Linus "the Grinch" Torvalds, 24 Dec 2000 on linux-kernel
