Re: lm sensors sysfs file structure

Greg KH
2003-04-01T06:32:44Z

On Sun, Mar 30, 2003 at 09:23:12PM +0200, Pavel Machek wrote:
> Hi!
>
> > > > Floating point values XXX.X or XXX.XX in degrees Celcius.
> > >
> > > If we're restructuring it, I think we should also agree on _one_ common
> > > denominator for all values ie. mVolt and milli-Degree Celsius, so that
> > > no userspace program ever again has know how to convert them to
> > > user-readable values and every user can just cat the values and doesn't
> > > have to wonder if it's centi-Volt, milli-Volt, centi-Degree, dezi-Degree
> > > or whatever.
> >
> > Um, that's what my proposal stated. Do you not agree with it? (You're
> > quoting the existing document above, not my proposed changes.)
>
> Well, you had cV for PSU voltages and
> mV for cpu core voltage. I guess mV
> and mili-deg-C everywhere would be
> nicer.

I was trying to keep consistant with what the old /proc values were
reported as. I'll go fix that up.

As for why no floating point, it's a pain in the but to both output a
fixed point number from the kernel into floating point, and to parse a
floating point number from userspace within the kernel, turning it into
a fixed point number. With the proposal I wrote up, none of that is
needed, and all userspace has to do is divide by a factor of 10 to get
the proper value.

It's much simpler and easier to validate we got it right code. If
you're still not convinced take a look at the code in
drivers/i2c/i2c-proc.c::i2c_parse_reals() for an example of some hairy
code...

thanks,

greg k-h