On Mon, Jul 19, 2010 at 06:44:31PM +0200, Takashi Iwai wrote:
The guess work isn't always trivial. If the hardware switches the curve between log and linear over a hole, which should be taken for a value in the hole? Whne TLV is given for the hole, at least it's a good hint.
I don't see what difference the curves make here? However the gap is expressed only the points at either end are selectable (and there's always the chance that this is part of a series of random individual points with no particular curve through them).
Personally I'd rather the kernel just provided a mapping between control values and dB scales and then the application layer can decide what it thinks an appropriate match is. Decisions about how accurate a match is needed seem very policy like and therefore userspaceish and it seems wrong to be coding the data tables in the kernel in a way that works around the particular match algorithm in the application layer.
User space can check the correctness always by checking the reverse conversion between dB <-> value again.
It still seems silly to have to paper over this for every single dB interval - if we need to link up the ranges it seems like we ought to be fixing this in one place.