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    SubjectRe: tp_smapi conflict with IDE, hdaps
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    On Maw, 2005-12-13 at 18:04 +0200, Shem Multinymous wrote:
    > > What else does that code do, what else might it confuse, what rules and
    > > locking are hidden in the windows driver that are unknown. Want to risk
    > > everyones data for that ?
    >
    > We already take that risk to some degree, since the SMAPI BIOS is also
    > invoked by the ACPI DSDT and by external events.

    But the ACPI DSDT is OS independant in theory and in practice to a fair
    extent. It can't make assumptions about windows drivers.

    > > HDAPS doesn't need it btw.
    >
    > It's not implemented yet, but I gather it's necessary for preventing
    > the disk from spinning back up as the laptop slides off the table.
    > Maybe I missed some subsequent discussion?

    HDAPS wants to be able to talk with the IDE/libata layer to request it
    to hold off requests, thats very different to "gee I wonder what the
    bios did"

    > You write "command" values into IO ports 0x1610 and 0x161F and, in
    > some cases, read some results from ports 0x1610-0x161F. Throughout
    > that, you inspect various bits (whose meaning we don't understand) in
    > the status port 0x1604. The details of the commands, scheduling and
    > status bits differ between the drivers. I don't think a full-blown
    > ownership and expansion infrastructure is necessary, or even possible
    > without better understanding.

    Ok


    > Thanks for the pointers. I guess the minimal approach is probably
    > ideal here; are there any such dumb drivers lying around?

    Its probably easier to write than go find one


    I mean you need


    tp_hw_init() {
    if (not a thinkpad) return -ENODEV
    request_region(...)
    return 0
    }

    tp_hw_exit() {
    release_region(...)
    }

    EXPORT_SYMBOL_GPL(tp_hw_lock);
    EXPORT_SYMBOL_GPL(tp_hw_unlock);

    tp_hw_lock() {
    down(&tp_sem);
    }

    tp_hw_unlock() {
    up(&tp_sem);
    }

    /* And perhaps if the port varies by machine */

    EXPORT_SYMBOL_GPL(tp_hw_addr);

    tp_hw_addr() {
    return 0x1600;
    }

    It can really be that simple

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