On Wed, Jun 11, 2003 at 06:29:10PM -0700, Philip Pokorny wrote: > Greg KH wrote: > >On Sat, Jun 07, 2003 at 02:21:54PM -0700, Philip Pokorny wrote: > > > >>As a follow up to my previous e-mail I thouht I would document some other > >>thoughts I had recently about the interface between the new sysfs based > >>drivers and libsensors and user-space applications. > >> > >>Not that any of these are particularly good ideas, I just wanted to get > >>them out there... > >> > >>1. If the library is to be able to deal with any value in a consistent > >>way, it needs to know if that value is in milli-degC, mVolts or whole > >>counts. While saying that all temperatures would now *have* to be > >>reported in milli-degC makes all temperatures consistent, there is still > >>the problem that all values are not scaled identically (fan's are in > >>whole RPM's). If each reading came with a scaling factor (1 to 1000 or > >>more) it would be possible to have a generic routine for converting a > >>driver integer to a user-space floating point value. > >> > >>I see two possibilities... > >> > >>Include the scaling in the same file with the reading: > > > > > >Ick, no. > > > >What's wrong with just using the same units always? > > Because not every reading has the same scaling. RPM's are unit scaled, > voltages are milli-volt scaled, temperatures will now be milli-degC > scaled. But the VRM spec is 10 scaled (8.1, 9.1, 10.0 etc) and auto fan > control will require time values for some parameters. milli-seconds for > all time parameters is not appropriate. Other values may require > different scaling as well. Why is milli-seconds not appropriate for all time parameters? Having constant units makes things a _lot_ easier for the user. > And for the library, it would be nice if the interface to sysfs didn't > have to worry about what "type" a reading was and make some arbitrary, > compiled in, decision about what the scaling for that value should be. > It is *much* more flexible and appropriate for the driver to inform the > library what the scaling for a given value is. Yes, it's more flexible. But we aren't going to allow multiple values per sysfs files, and I don't think you really want to add yet more sysfs files per sensor value :) thanks, greg k-h
