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    SubjectRe: [PATCH v2] Re: Battery class driver.
    Hi Greg,

    On 10/31/06, Greg KH <> wrote:
    > > On 10/28/06, David Zeuthen <> wrote:
    > > >What about just prepending the unit to the 'threshold' file? Then user
    > > >space can expect the contents of said file to be of the form "%d %s". I
    > > >don't think that violates the "only one value per file" sysfs mantra.
    > >
    > > The tp_smapi battery driver did just this ("16495 mW"). But I dropped
    > > it in a recent version when Pavel pointed out the rest of sysfs, hwmon
    > > included, uses undecorated integers.
    > > Consistency aside, it seems reasonable and convenient. You have to
    > > decree that writes to the attributes (where relevant) don't include
    > > the units, of course, so no one will expect the kernel to parse that.
    > >
    > > There's an issue here if a drunk driver decides to specify (say)
    > > capacity_remaining in mWh and capacity_last_full in mAa, which will
    > > confuse anyone comparing those attributest. So don't do that.
    > >
    > > Jean, what's your opinion on letting hwmon-ish attributes specify
    > > units as "%d %s" where these are hardware-dependent?
    > No, the sysfs files should just always keep the same units as
    > documented. It's easier all around that way.

    It sure is easier, but we're discussinng the case where units change
    in runtime; what do we document then? Plug in a different battery and
    you get reports in mA and mAh insted of mW and mWh.

    The suggestions so far were:
    1. Append units string to the content of such attribute:
    /sys/.../capacity_remaining reads "16495 mW".
    2. Add a seprate *_units attribute saying what are units for other attribute:
    /sys/.../capacity_units gives the units for
    3. Append the units to the attribute names:

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      Last update: 2006-10-31 14:31    [W:0.024 / U:2.912 seconds]
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