linux/Documentation/ABI/testing/sysfs-bus-wmi
Armin Wolf 618ba6abfc
platform/x86: wmi: Add bus ABI documentation
Add documentation for the WMI bus sysfs interface so userspace
applications can use it to access additional data about WMI devices.

Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Armin Wolf <W_Armin@gmx.de>
Link: https://lore.kernel.org/r/20240624173116.31314-3-W_Armin@gmx.de
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
2024-06-24 20:36:13 +03:00

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What: /sys/bus/wmi/devices/.../driver_override
Date: February 2024
Contact: Armin Wolf <W_Armin@gmx.de>
Description:
This file allows the driver for a device to be specified which
will override standard ID table matching.
When specified, only a driver with a name matching the value
written to driver_override will have an opportunity to bind
to the device.
The override is specified by writing a string to the
driver_override file (echo wmi-event-dummy > driver_override).
The override may be cleared with an empty string (echo > \
driver_override) which returns the device to standard matching
rules binding.
Writing to driver_override does not automatically unbind the
device from its current driver or make any attempt to automatically
load the specified driver. If no driver with a matching name is
currently loaded in the kernel, the device will not bind to any
driver.
This also allows devices to opt-out of driver binding using a
driver_override name such as "none". Only a single driver may be
specified in the override, there is no support for parsing delimiters.
What: /sys/bus/wmi/devices/.../modalias
Date: November 20:15
Contact: Andy Lutomirski <luto@kernel.org>
Description:
This file contains the MODALIAS value emitted by uevent for a
given WMI device.
Format: wmi:XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX.
What: /sys/bus/wmi/devices/.../guid
Date: November 2015
Contact: Andy Lutomirski <luto@kernel.org>
Description:
This file contains the GUID used to match WMI devices to
compatible WMI drivers. This GUID is not necessarily unique
inside a given machine, it is solely used to identify the
interface exposed by a given WMI device.
What: /sys/bus/wmi/devices/.../object_id
Date: November 2015
Contact: Andy Lutomirski <luto@kernel.org>
Description:
This file contains the WMI object ID used internally to construct
the ACPI method names used by non-event WMI devices. It contains
two ASCII letters.
What: /sys/bus/wmi/devices/.../notify_id
Date: November 2015
Contact: Andy Lutomirski <luto@kernel.org>
Description:
This file contains the WMI notify ID used internally to map ACPI
events to WMI event devices. It contains two ASCII letters.
What: /sys/bus/wmi/devices/.../instance_count
Date: November 2015
Contact: Andy Lutomirski <luto@kernel.org>
Description:
This file contains the number of WMI object instances being
present on a given WMI device. It contains a non-negative
number.
What: /sys/bus/wmi/devices/.../expensive
Date: November 2015
Contact: Andy Lutomirski <luto@kernel.org>
Description:
This file contains a boolean flag signaling if interacting with
the given WMI device will consume significant CPU resources.
The WMI driver core will take care of enabling/disabling such
WMI devices.
What: /sys/bus/wmi/devices/.../setable
Date: May 2017
Contact: Darren Hart (VMware) <dvhart@infradead.org>
Description:
This file contains a boolean flags signaling the data block
aassociated with the given WMI device is writable. If the
given WMI device is not associated with a data block, then
this file will not exist.