On 10/01/2018 11:27 AM, Helmut Grohne wrote: > On Fri, Sep 28, 2018 at 04:00:17PM +0200, Hans Verkuil wrote: >> On 09/25/2018 12:14 PM, Sakari Ailus wrote: >>> +/* V4L2 control unit prefixes */ >>> +#define V4L2_CTRL_PREFIX_NANO -9 >>> +#define V4L2_CTRL_PREFIX_MICRO -6 >>> +#define V4L2_CTRL_PREFIX_MILLI -3 >>> +#define V4L2_CTRL_PREFIX_1 0 >> >> I would prefer PREFIX_NONE, since there is no prefix in this case. >> >> I assume this prefix is only valid if the unit is not UNDEFINED and not >> NONE? > > Why should it? The prefix is concerned with rescaling a value prior to > presenting it to a user. Even a unitless quantity or a value of > undefined unit can be reasonably scaled. Displaying a unit and scaling > look like orthogonal concepts to me. What's the point? If I have a unit-less control with values 1-1000, then what would a prefix 'milli' tell me as a user? Why would 0.001-1 be better compared to 1-1000? Without a unit it is just an integer range and scaling is meaningless. > >> Is 'base' also dependent on a valid unit? (it doesn't appear to be) > > I'd argue it should not depend on a valid unit like the prefix. I think I agree with that, although I am dubious about the value of the base field as I commented on elsewhere. Regards, Hans
