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    SubjectRe: [Hdaps-devel] [PATCH 2.6.23-rc2] hwmon: HP Mobile Data Protection System 3D ACPI driver (resend)
    Shem Multinymous wrote:
    > On 8/29/07, Henrique de Moraes Holschuh <hmh@hmh.eng.br> wrote:
    >
    >> On Wed, 29 Aug 2007, Yan Burman wrote:
    >>
    >
    >
    >> HDAPS with input device support is quite new. hdapsd was patched to talk to
    >> it, too. I suppose we should port the input device support to the driver
    >> in-tree just so that we get it in tree as well. Sounds like an useful
    >> reason to bother with in-tree hdaps. Not that it will save much power with
    >> the in-tree driver, but at least it will be widely available from there.
    >>
    >
    > In case they'll be of help for such porting, the relevant hdaps
    > patches from my tp_smapi patch series are attached.
    >
    >
    >
    >>> I agree that the sys interface is probably not the best choice, but the
    >>> accelerometer data should provide not only position, but also generate
    >>> an event when it detects
    >>> that it's falling. From what I understood hdaps does not have that info,
    >>>
    >> You can generate events on input devices, but I am not sure that's the best
    >> way to go about it for this. Things that block on read until an interrupt
    >> happens might work better.
    >>
    >
    > You can do the latter via another (4th) input device.
    >
    >
    >
    What's wrong with the stuff I did in mdps? a misc character device that
    acts like /dev/rtc. Why does it have to be input device oriented?
    >> I'd suggest an accelerometer sysfs interface, that we implement in hdaps
    >> (in and out-of-tree), ams and hpmdp. One input device for joystick
    >> emulation (optional), one input device with accelerometer data in mg or ug,
    >>
    >
    > Is any of the accelerometer drivers currently capable of computing the
    > physical acceleration? Also, is there an issue of linear vs. angular
    > acceleration?
    >
    >
    >
    >> and an optional one with the raw accelerometer data.
    >>
    >
    > Before or after axis inversion/swapping? The tp_smapi hdaps driver
    > (losslessly) inverts the raw data too, to avoid duplication of
    > model-specific orientation logic.
    >
    >
    >
    >> unless someone wants to implement their own free-fall algorithms instead of
    >> using whatever is in the firmware).
    >>
    >
    > The term "free-fall" is dangerously misleading, for the reasons
    > explained in the IBM APS whitepaper.
    >
    > Shem
    >

    I also looked at what you did in the patches as well as the modified
    hdapsd. I'm doing the raw input device right now in the mdps, but I have
    a suggestion.
    It seems to me that right now there are at least 3 drivers that provide
    the same functionality - hdaps, ams and mdps. Why not create the input
    device
    that exports raw accelerometer data with a name that is generic -
    something like accel/input or something along those lines. This way
    hdapsd could work
    with any driver that provides the functionality without being hdaps
    specific.

    Yan
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