Em Fri, 11 Sep 2009 21:23:44 +0200 Hans Verkuil <hverkuil@xxxxxxxxx> escreveu: > > In the case of resizer, I don't see why this can't be implemented as an ioctl > > over /dev/video device. > > Well, no. Not in general. There are two problems. The first problem occurs if > you have multiple instances of a resizer (OK, not likely, but you *can* have > multiple video encoders or decoders or sensors). If all you have is the > streaming device node, then you cannot select to which resizer (or video > encoder) the ioctl should go. The media controller allows you to select the > recipient of the ioctl explicitly. Thus providing the control that these > applications need. This case doesn't apply, since, if you have multiple encoders and/or decoders, you'll also have multiple /dev/video instances. All you need is to call it at the right device you need to control. Am I missing something here? > The second problem is that this will pollute the 'namespace' of a v4l device > node. Device drivers need to pass all those private ioctls to the right > sub-device. But they shouldn't have to care about that. If someone wants to > tweak the resizer (e.g. scaling coefficients), then pass it straight to the > resizer component. Sorry, I missed your point here Cheers, Mauro -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
