Hi all! Recently I had to add two new ioctls for the subdev API (include/linux/v4l2-subdev.h) and I noticed that the numbering of the ioctls was somewhat random. In most cases the ioctl number was the same as the V4L2 API counterpart, but for subdev-specific ioctls no rule exists. There are a few problems with this: because of the lack of rules there is a chance that in the future a subdev ioctl may end up to be identical to an existing V4L2 ioctl. Also, because the numbering isn't nicely increasing it makes it hard to create a lookup table as was done for the V4L2 ioctls. Well, you could do it, but it would be a very sparse array, wasting a lot of memory. Lookup tables have proven to be very useful, so we might want to introduce them for the subdev core code as well in the future. Since the subdev API is still marked experimental, I propose to renumber the ioctls and use the letter 'v' instead of 'V'. 'v' was used for V4L1, and so it is now available for reuse. We keep the old ioctls around for a few kernel cycles, and remove them some time next year. Note that some V4L2 ioctls are also available for use in the subdev API (control ioctls in particular). By using a different letter for the ioctls this will make it easy as well to decide what lookup table to use should we decide to introduce that in the subdev core code in the future. Comments? Regards, Hans -- 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
