On Thu, 25 Oct 2001 volodya@xxxxxxxxxxxxxx wrote: > > After looking at and working with Xv, v4l and v4l2 I became somewhat > dissatisfied with the current state of affairs. I have attached a > description of the API that would make (at least) me much happier. > > I would very much appreciate comments from interested people.. I'm not a coder for Linux or X, but I figured this would be a good read anyway, as it might provide some ideas for a similar (albeit less complex) issue on another platform I use >:-) Anyways since this is an RFC, here's the only a couple of comments I can think of (the RFC otherwise looks clear to me): Commands/queries should also include some kind of (arbitrary, decided by the calling program) command serial number, so that an out-of-sequence reply (those prepended with a colon as you describe) can be matched to a previous command/query. This could allow several commands to be sent and handled by multiple processes/threads/whatever. 05,HUE=7\n 07,some unrelated command +05\n # The HUE command was successful :07,reply to unrelated command :05,HUE=6\n # Driver reported the HUE parameter as # different from that most recently set. The program wanted to set HUE to 7, command successful, value later returned was 6 (maybe the device only allows even values), while at the same time some other command was sent and processed. Also, it might be a nice idea to return the range of one or more parameters if a command given is out of range. Suppose HUE is only valid for values 0-255: 06,HUE=300\n -06,HUE=INVALID,0,255\n ..Would tell the calling program that a value given for HUE is only valid for a range of 0 to 255. This would be useful for a program that wants to attempt to guess the range a device accepts for a given parameter. -- _________________________ ___ ___ | natedac@xxxxxxxxxxx //ZZ]__ | | C64/C128/SCPU |'/ |Z/ | | What's *YOUR* Hobby!? | \__|_\ | |_________________________\___]___|
