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    SubjectRe: [PATCH] Disable i8042 checks on Intel Apple Macs
    On Wed, Jan 20, 2010 at 7:31 PM, Bastien Nocera <> wrote:
    > On Wed, 2010-01-20 at 18:41 -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<>
    >> 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
    > Actually, the error message is "i8042.c: No controller found". Which
    > happens very early in a sub-function of i8042_init().
    > So I don't think this would solve the problem.

    That message comes out of i8042_controller_check which gets called
    after i8042_platform_init, which does the check above. So it appears
    either the "PNP: No PS/2 controller found" message should have been
    printed or PNP did in fact show a controller is present..

    >> 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. 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).
    > They might also have a better BIOS than the Macs and avoid hanging when
    > that happens...
    >> I can see continuing on and probing if PNP isn't present on the machine,
    >> but certainly if ACPI is enabled, I don't think we should be doing such
    >> things.
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