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    SubjectRe: [PATCH] Disable i8042 checks on Intel Apple Macs
    From
    On Thu, Jan 21, 2010 at 3:49 PM, Justin P. Mattock
    <justinmattock@gmail.com> wrote:
    > On 01/21/10 13:39, Robert Hancock wrote:
    >>
    >> On Thu, Jan 21, 2010 at 12:55 PM, Dmitry Torokhov
    >> <dmitry.torokhov@gmail.com>  wrote:
    >>>
    >>> On Wed, Jan 20, 2010 at 06:41:56PM -0600, Robert Hancock wrote:
    >>>>
    >>>> On 01/20/2010 12:23 PM, Bastien Nocera wrote:
    >>>>>
    >>>>> As those computers never had any i8042 controllers, and the
    >>>>> current lookup code could potentially lock up/hang/wait for
    >>>>> timeout for long periods of time.
    >>>>>
    >>>>> Fixes intermittent hangs on boot on a MacbookAir1,1
    >>>>>
    >>>>> Signed-off-by: Bastien Nocera<hadess@hadess.net>
    >>>>
    >>>> I assume this is happening because of this code in
    >>>> drivers/input/serio/i8042-x86ia64io.h:
    >>>>
    >>>>         if (!i8042_pnp_kbd_devices&&  !i8042_pnp_aux_devices) {
    >>>>                 i8042_pnp_exit();
    >>>> #if defined(__ia64__)
    >>>>                 return -ENODEV;
    >>>> #else
    >>>>                 printk(KERN_INFO "PNP: No PS/2 controller found.
    >>>> Probing ports directly.\n");
    >>>>                 return 0;
    >>>> #endif
    >>>>
    >>>> In other words, on x86, if PNP and/or ACPI don't indicate any PS/2
    >>>> controller exists, we randomly bang on the ports in the expectation
    >>>> they'll be there anyway. This seems rather misguided.
    >>>
    >>> Basically, we do not trust BIOS writers on x86 ;) In the past there were
    >>> occasions when they forgot to mention presence of KBD/AUX in DSDT and
    >>> elsewhere which lead to non-functional keyboard/mouse.
    >>
    >> Are we certain about that? Any pointers to reports?
    >>
    >>>
    >>>> It would seem
    >>>> like a better idea to fix this rather than adding yet another DMI
    >>>> list (especially since there likely are, or will be, machines
    >>>> without i8042 other than Macs).
    >>>>
    >>>
    >>> If they are not Macs that mean they are tested with windows and thus
    >>> expect probes in i8042 port region so no harm done. In a few years if
    >>> everyone uses USB only we could add a year threshold to trust ACPI/PNP
    >>> data.
    >>
    >> Macs will be tested with Windows too, so obviously it manages to avoid
    >> this problem somehow, and I very much doubt it has an Apple-specific
    >> check..
    >> --
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    >> Please read the FAQ at  http://www.tux.org/lkml/
    >>
    >
    > I've an iMac, and a macbook over here,
    > if you guys need me to test out a patch for this let me know.

    Can you (and probably Bastien or whoever had the problematic machine)
    check the output of:

    cat /sys/bus/pnp/devices/*/id
    and see if any of these are present?

    PNP0303
    PNP030b
    FJC6000
    FJC6001
    PNP0f03
    PNP0f0b
    PNP0f0e
    PNP0f12
    PNP0f13
    PNP0f19
    PNP0f1c
    SYN0801
    --
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