cvs commit: src/sys/dev/acpica acpi_ec.c

[Nate Lawson]

On Mon, 21 Jul 2003, John Baldwin wrote:
> On 20-Jul-2003 Nate Lawson wrote:
> >   Modified files:
> >     sys/dev/acpica       acpi_ec.c
> >   Log:
> >   Do not call acpi_MatchHid() for all probe cases since it accesses the
> >   namespace.  To compensate for it only being used in the !ECDT case, use
> >   a more robust approach to indicate a device was probed via ECDT by setting
> >   the private ivar to be &acpi_ec_devclass.  Without the acpi_MatchHid() call
> >   now, it might have been possible for a non-EC device to have had its magic
> >   match our previous flag.
> >
> >   Pointed out by:         takawata
>
> Assuming you are doing a device_add_child() to add the ec, you could add it
> with the name "acpi_ec" and then only the ec driver would probe it.

I do add it with that name but that doesn't prevent it from getting a
duplicate probe when the namespace is evaluated (much later).

The sequence with ECDT is:
acpi_attach()
acpi_ec_ecdt_probe()
    if ECDT present
       device_add_child("acpi_ec")
       device_probe_and_attach()
           acpi_ec_probe()
               if ECDT magic set in ivars
                  done
           acpi_ec_attach()
               allocate resources
...
namespace started
...
walk all devices, _STA, _INI
    acpi_ec_probe()    <===== same device as already probed above
        if lookup devclass finds duplicate for _UID
            ENXIO; don't attach again

-Nate