diff options
| author | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2016-11-30 02:52:38 +0100 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2016-12-06 02:13:28 +0100 |
| commit | ee39222d45839284f91e882df8a985e1af0f7e18 (patch) | |
| tree | 5fada60dc79c35d110c3287ad478c8b30c1cb0a2 /Documentation/acpi/enumeration.txt | |
| parent | 99db5ff7fe0b4e1657423d7bbe2aa8f655dd02d1 (diff) | |
ACPI / property: Document usage rules for _DSD properties
Following some discussions during the Kernel Summit and LPC, document
what can be returned from ACPI _DSD as device properties and when it
is valid to use the special PRP0001 device ID.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviwed-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'Documentation/acpi/enumeration.txt')
| -rw-r--r-- | Documentation/acpi/enumeration.txt | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/Documentation/acpi/enumeration.txt b/Documentation/acpi/enumeration.txt index a91ec5af52df..209a5eba6b87 100644 --- a/Documentation/acpi/enumeration.txt +++ b/Documentation/acpi/enumeration.txt @@ -415,3 +415,12 @@ the "compatible" property in the _DSD or a _CID as long as one of their ancestors provides a _DSD with a valid "compatible" property. Such device objects are then simply regarded as additional "blocks" providing hierarchical configuration information to the driver of the composite ancestor device. + +However, PRP0001 can only be returned from either _HID or _CID of a device +object if all of the properties returned by the _DSD associated with it (either +the _DSD of the device object itself or the _DSD of its ancestor in the +"composite device" case described above) can be used in the ACPI environment. +Otherwise, the _DSD itself is regarded as invalid and therefore the "compatible" +property returned by it is meaningless. + +Refer to DSD-properties-rules.txt for more information. |