295 lines
11 KiB
ReStructuredText
295 lines
11 KiB
ReStructuredText
.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
|
|
.. c:namespace:: CEC
|
|
|
|
.. _CEC_MODE:
|
|
.. _CEC_G_MODE:
|
|
.. _CEC_S_MODE:
|
|
|
|
********************************
|
|
ioctls CEC_G_MODE and CEC_S_MODE
|
|
********************************
|
|
|
|
CEC_G_MODE, CEC_S_MODE - Get or set exclusive use of the CEC adapter
|
|
|
|
Synopsis
|
|
========
|
|
|
|
.. c:macro:: CEC_G_MODE
|
|
|
|
``int ioctl(int fd, CEC_G_MODE, __u32 *argp)``
|
|
|
|
.. c:macro:: CEC_S_MODE
|
|
|
|
``int ioctl(int fd, CEC_S_MODE, __u32 *argp)``
|
|
|
|
Arguments
|
|
=========
|
|
|
|
``fd``
|
|
File descriptor returned by :c:func:`open()`.
|
|
|
|
``argp``
|
|
Pointer to CEC mode.
|
|
|
|
Description
|
|
===========
|
|
|
|
By default any filehandle can use :ref:`CEC_TRANSMIT`, but in order to prevent
|
|
applications from stepping on each others toes it must be possible to
|
|
obtain exclusive access to the CEC adapter. This ioctl sets the
|
|
filehandle to initiator and/or follower mode which can be exclusive
|
|
depending on the chosen mode. The initiator is the filehandle that is
|
|
used to initiate messages, i.e. it commands other CEC devices. The
|
|
follower is the filehandle that receives messages sent to the CEC
|
|
adapter and processes them. The same filehandle can be both initiator
|
|
and follower, or this role can be taken by two different filehandles.
|
|
|
|
When a CEC message is received, then the CEC framework will decide how
|
|
it will be processed. If the message is a reply to an earlier
|
|
transmitted message, then the reply is sent back to the filehandle that
|
|
is waiting for it. In addition the CEC framework will process it.
|
|
|
|
If the message is not a reply, then the CEC framework will process it
|
|
first. If there is no follower, then the message is just discarded and a
|
|
feature abort is sent back to the initiator if the framework couldn't
|
|
process it. If there is a follower, then the message is passed on to the
|
|
follower who will use :ref:`ioctl CEC_RECEIVE <CEC_RECEIVE>` to dequeue
|
|
the new message. The framework expects the follower to make the right
|
|
decisions.
|
|
|
|
The CEC framework will process core messages unless requested otherwise
|
|
by the follower. The follower can enable the passthrough mode. In that
|
|
case, the CEC framework will pass on most core messages without
|
|
processing them and the follower will have to implement those messages.
|
|
There are some messages that the core will always process, regardless of
|
|
the passthrough mode. See :ref:`cec-core-processing` for details.
|
|
|
|
If there is no initiator, then any CEC filehandle can use
|
|
:ref:`ioctl CEC_TRANSMIT <CEC_TRANSMIT>`. If there is an exclusive
|
|
initiator then only that initiator can call
|
|
:ref:`CEC_TRANSMIT`. The follower can of course
|
|
always call :ref:`ioctl CEC_TRANSMIT <CEC_TRANSMIT>`.
|
|
|
|
Available initiator modes are:
|
|
|
|
.. tabularcolumns:: |p{5.6cm}|p{0.9cm}|p{10.8cm}|
|
|
|
|
.. _cec-mode-initiator_e:
|
|
|
|
.. flat-table:: Initiator Modes
|
|
:header-rows: 0
|
|
:stub-columns: 0
|
|
:widths: 3 1 16
|
|
|
|
* .. _`CEC-MODE-NO-INITIATOR`:
|
|
|
|
- ``CEC_MODE_NO_INITIATOR``
|
|
- 0x0
|
|
- This is not an initiator, i.e. it cannot transmit CEC messages or
|
|
make any other changes to the CEC adapter.
|
|
* .. _`CEC-MODE-INITIATOR`:
|
|
|
|
- ``CEC_MODE_INITIATOR``
|
|
- 0x1
|
|
- This is an initiator (the default when the device is opened) and
|
|
it can transmit CEC messages and make changes to the CEC adapter,
|
|
unless there is an exclusive initiator.
|
|
* .. _`CEC-MODE-EXCL-INITIATOR`:
|
|
|
|
- ``CEC_MODE_EXCL_INITIATOR``
|
|
- 0x2
|
|
- This is an exclusive initiator and this file descriptor is the
|
|
only one that can transmit CEC messages and make changes to the
|
|
CEC adapter. If someone else is already the exclusive initiator
|
|
then an attempt to become one will return the ``EBUSY`` error code
|
|
error.
|
|
|
|
Available follower modes are:
|
|
|
|
.. tabularcolumns:: |p{6.6cm}|p{0.9cm}|p{9.8cm}|
|
|
|
|
.. _cec-mode-follower_e:
|
|
|
|
.. cssclass:: longtable
|
|
|
|
.. flat-table:: Follower Modes
|
|
:header-rows: 0
|
|
:stub-columns: 0
|
|
:widths: 3 1 16
|
|
|
|
* .. _`CEC-MODE-NO-FOLLOWER`:
|
|
|
|
- ``CEC_MODE_NO_FOLLOWER``
|
|
- 0x00
|
|
- This is not a follower (the default when the device is opened).
|
|
* .. _`CEC-MODE-FOLLOWER`:
|
|
|
|
- ``CEC_MODE_FOLLOWER``
|
|
- 0x10
|
|
- This is a follower and it will receive CEC messages unless there
|
|
is an exclusive follower. You cannot become a follower if
|
|
:ref:`CEC_CAP_TRANSMIT <CEC-CAP-TRANSMIT>` is not set or if :ref:`CEC_MODE_NO_INITIATOR <CEC-MODE-NO-INITIATOR>`
|
|
was specified, the ``EINVAL`` error code is returned in that case.
|
|
* .. _`CEC-MODE-EXCL-FOLLOWER`:
|
|
|
|
- ``CEC_MODE_EXCL_FOLLOWER``
|
|
- 0x20
|
|
- This is an exclusive follower and only this file descriptor will
|
|
receive CEC messages for processing. If someone else is already
|
|
the exclusive follower then an attempt to become one will return
|
|
the ``EBUSY`` error code. You cannot become a follower if
|
|
:ref:`CEC_CAP_TRANSMIT <CEC-CAP-TRANSMIT>` is not set or if :ref:`CEC_MODE_NO_INITIATOR <CEC-MODE-NO-INITIATOR>`
|
|
was specified, the ``EINVAL`` error code is returned in that case.
|
|
* .. _`CEC-MODE-EXCL-FOLLOWER-PASSTHRU`:
|
|
|
|
- ``CEC_MODE_EXCL_FOLLOWER_PASSTHRU``
|
|
- 0x30
|
|
- This is an exclusive follower and only this file descriptor will
|
|
receive CEC messages for processing. In addition it will put the
|
|
CEC device into passthrough mode, allowing the exclusive follower
|
|
to handle most core messages instead of relying on the CEC
|
|
framework for that. If someone else is already the exclusive
|
|
follower then an attempt to become one will return the ``EBUSY`` error
|
|
code. You cannot become a follower if :ref:`CEC_CAP_TRANSMIT <CEC-CAP-TRANSMIT>`
|
|
is not set or if :ref:`CEC_MODE_NO_INITIATOR <CEC-MODE-NO-INITIATOR>` was specified,
|
|
the ``EINVAL`` error code is returned in that case.
|
|
* .. _`CEC-MODE-MONITOR-PIN`:
|
|
|
|
- ``CEC_MODE_MONITOR_PIN``
|
|
- 0xd0
|
|
- Put the file descriptor into pin monitoring mode. Can only be used in
|
|
combination with :ref:`CEC_MODE_NO_INITIATOR <CEC-MODE-NO-INITIATOR>`,
|
|
otherwise the ``EINVAL`` error code will be returned.
|
|
This mode requires that the :ref:`CEC_CAP_MONITOR_PIN <CEC-CAP-MONITOR-PIN>`
|
|
capability is set, otherwise the ``EINVAL`` error code is returned.
|
|
While in pin monitoring mode this file descriptor can receive the
|
|
``CEC_EVENT_PIN_CEC_LOW`` and ``CEC_EVENT_PIN_CEC_HIGH`` events to see the
|
|
low-level CEC pin transitions. This is very useful for debugging.
|
|
This mode is only allowed if the process has the ``CAP_NET_ADMIN``
|
|
capability. If that is not set, then the ``EPERM`` error code is returned.
|
|
* .. _`CEC-MODE-MONITOR`:
|
|
|
|
- ``CEC_MODE_MONITOR``
|
|
- 0xe0
|
|
- Put the file descriptor into monitor mode. Can only be used in
|
|
combination with :ref:`CEC_MODE_NO_INITIATOR <CEC-MODE-NO-INITIATOR>`,
|
|
otherwise the ``EINVAL`` error code will be returned.
|
|
In monitor mode all messages this CEC
|
|
device transmits and all messages it receives (both broadcast
|
|
messages and directed messages for one its logical addresses) will
|
|
be reported. This is very useful for debugging. This is only
|
|
allowed if the process has the ``CAP_NET_ADMIN`` capability. If
|
|
that is not set, then the ``EPERM`` error code is returned.
|
|
* .. _`CEC-MODE-MONITOR-ALL`:
|
|
|
|
- ``CEC_MODE_MONITOR_ALL``
|
|
- 0xf0
|
|
- Put the file descriptor into 'monitor all' mode. Can only be used
|
|
in combination with :ref:`CEC_MODE_NO_INITIATOR <CEC-MODE-NO-INITIATOR>`, otherwise
|
|
the ``EINVAL`` error code will be returned. In 'monitor all' mode all messages
|
|
this CEC device transmits and all messages it receives, including
|
|
directed messages for other CEC devices, will be reported. This is
|
|
very useful for debugging, but not all devices support this. This
|
|
mode requires that the :ref:`CEC_CAP_MONITOR_ALL <CEC-CAP-MONITOR-ALL>` capability is set,
|
|
otherwise the ``EINVAL`` error code is returned. This is only allowed if
|
|
the process has the ``CAP_NET_ADMIN`` capability. If that is not
|
|
set, then the ``EPERM`` error code is returned.
|
|
|
|
Core message processing details:
|
|
|
|
.. tabularcolumns:: |p{6.6cm}|p{10.9cm}|
|
|
|
|
.. _cec-core-processing:
|
|
|
|
.. flat-table:: Core Message Processing
|
|
:header-rows: 0
|
|
:stub-columns: 0
|
|
:widths: 1 8
|
|
|
|
* .. _`CEC-MSG-GET-CEC-VERSION`:
|
|
|
|
- ``CEC_MSG_GET_CEC_VERSION``
|
|
- The core will return the CEC version that was set with
|
|
:ref:`ioctl CEC_ADAP_S_LOG_ADDRS <CEC_ADAP_S_LOG_ADDRS>`,
|
|
except when in passthrough mode. In passthrough mode the core
|
|
does nothing and this message has to be handled by a follower
|
|
instead.
|
|
* .. _`CEC-MSG-GIVE-DEVICE-VENDOR-ID`:
|
|
|
|
- ``CEC_MSG_GIVE_DEVICE_VENDOR_ID``
|
|
- The core will return the vendor ID that was set with
|
|
:ref:`ioctl CEC_ADAP_S_LOG_ADDRS <CEC_ADAP_S_LOG_ADDRS>`,
|
|
except when in passthrough mode. In passthrough mode the core
|
|
does nothing and this message has to be handled by a follower
|
|
instead.
|
|
* .. _`CEC-MSG-ABORT`:
|
|
|
|
- ``CEC_MSG_ABORT``
|
|
- The core will return a Feature Abort message with reason
|
|
'Feature Refused' as per the specification, except when in
|
|
passthrough mode. In passthrough mode the core does nothing
|
|
and this message has to be handled by a follower instead.
|
|
* .. _`CEC-MSG-GIVE-PHYSICAL-ADDR`:
|
|
|
|
- ``CEC_MSG_GIVE_PHYSICAL_ADDR``
|
|
- The core will report the current physical address, except when
|
|
in passthrough mode. In passthrough mode the core does nothing
|
|
and this message has to be handled by a follower instead.
|
|
* .. _`CEC-MSG-GIVE-OSD-NAME`:
|
|
|
|
- ``CEC_MSG_GIVE_OSD_NAME``
|
|
- The core will report the current OSD name that was set with
|
|
:ref:`ioctl CEC_ADAP_S_LOG_ADDRS <CEC_ADAP_S_LOG_ADDRS>`,
|
|
except when in passthrough mode. In passthrough mode the core
|
|
does nothing and this message has to be handled by a follower
|
|
instead.
|
|
* .. _`CEC-MSG-GIVE-FEATURES`:
|
|
|
|
- ``CEC_MSG_GIVE_FEATURES``
|
|
- The core will do nothing if the CEC version is older than 2.0,
|
|
otherwise it will report the current features that were set with
|
|
:ref:`ioctl CEC_ADAP_S_LOG_ADDRS <CEC_ADAP_S_LOG_ADDRS>`,
|
|
except when in passthrough mode. In passthrough mode the core
|
|
does nothing (for any CEC version) and this message has to be handled
|
|
by a follower instead.
|
|
* .. _`CEC-MSG-USER-CONTROL-PRESSED`:
|
|
|
|
- ``CEC_MSG_USER_CONTROL_PRESSED``
|
|
- If :ref:`CEC_CAP_RC <CEC-CAP-RC>` is set and if
|
|
:ref:`CEC_LOG_ADDRS_FL_ALLOW_RC_PASSTHRU <CEC-LOG-ADDRS-FL-ALLOW-RC-PASSTHRU>`
|
|
is set, then generate a remote control key
|
|
press. This message is always passed on to the follower(s).
|
|
* .. _`CEC-MSG-USER-CONTROL-RELEASED`:
|
|
|
|
- ``CEC_MSG_USER_CONTROL_RELEASED``
|
|
- If :ref:`CEC_CAP_RC <CEC-CAP-RC>` is set and if
|
|
:ref:`CEC_LOG_ADDRS_FL_ALLOW_RC_PASSTHRU <CEC-LOG-ADDRS-FL-ALLOW-RC-PASSTHRU>`
|
|
is set, then generate a remote control key
|
|
release. This message is always passed on to the follower(s).
|
|
* .. _`CEC-MSG-REPORT-PHYSICAL-ADDR`:
|
|
|
|
- ``CEC_MSG_REPORT_PHYSICAL_ADDR``
|
|
- The CEC framework will make note of the reported physical address
|
|
and then just pass the message on to the follower(s).
|
|
|
|
|
|
Return Value
|
|
============
|
|
|
|
On success 0 is returned, on error -1 and the ``errno`` variable is set
|
|
appropriately. The generic error codes are described at the
|
|
:ref:`Generic Error Codes <gen-errors>` chapter.
|
|
|
|
The :ref:`ioctl CEC_S_MODE <CEC_S_MODE>` can return the following
|
|
error codes:
|
|
|
|
EINVAL
|
|
The requested mode is invalid.
|
|
|
|
EPERM
|
|
Monitor mode is requested, but the process does have the ``CAP_NET_ADMIN``
|
|
capability.
|
|
|
|
EBUSY
|
|
Someone else is already an exclusive follower or initiator.
|