I don't remember all of the details on this, but I will look at it and get back to you.
>-----Original Message-----
>From: Zhang, Rui
>Sent: Monday, September 20, 2010 12:08 AM
>To: Moore, Robert
>Cc: linux-acpi@xxxxxxxxxxxxxxx; Lin, Ming M; Brown, Len
>Subject: Why is Scope(_TZ_) defined as ACPI_TYPE_THERMAL rather than
>ACPI_TYPE_LOCAL_SCOPE
>
>Hi, Bob,
>
>this is the code in utglobal.c,
>/*
> * Predefined ACPI Names (Built-in to the Interpreter)
> *
> * NOTES:
> * 1) _SB_ is defined to be a device to allow \_SB_._INI to be run
> * during the initialization sequence.
> * 2) _TZ_ is defined to be a thermal zone in order to allow ASL code to
> * perform a Notify() operation on it.
> */
>const struct acpi_predefined_names acpi_gbl_pre_defined_names[] = {
> {"_GPE", ACPI_TYPE_LOCAL_SCOPE, NULL},
> {"_PR_", ACPI_TYPE_LOCAL_SCOPE, NULL},
> {"_SB_", ACPI_TYPE_DEVICE, NULL},
> {"_SI_", ACPI_TYPE_LOCAL_SCOPE, NULL},
> {"_TZ_", ACPI_TYPE_THERMAL, NULL},
> {"_REV", ACPI_TYPE_INTEGER, (char *)ACPI_CA_SUPPORT_LEVEL},
> {"_OS_", ACPI_TYPE_STRING, ACPI_OS_NAME},
> {"_GL_", ACPI_TYPE_MUTEX, (char *)1},
>
>I found a problem that Linux thermal driver tries to probe _TZ_ because
>the _TZ_ ACPI namespace node type suggests it's a thermal device.
>
>I'm wondering why it's a device rather than a scope.
>The comment above says ASL code may perform a Notify() operation on it,
>but IMO, this notification is meaningless on its own, because _TZ_ can
>neither detect the temperature, nor cool the system down, i.e. no action
>should be taken on this notification.
>
>So I think we should change the type to ACPI_TYPE_LOCAL_SCOPE, just like
>_PR_, _GPE.
>
>BTW: yes, we can do the tricks in Linux/ACPI code, but it's more likely
>an ACPICA problem. what do you think?
>
>thanks,
>rui
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