path: root/staging/drm-lease/drm-lease-v1.xml

<?xml version="1.0" encoding="UTF-8"?>
<protocol name="drm_lease_v1">
  <copyright>
    Copyright © 2018 NXP
    Copyright © 2019 Status Research &amp; Development GmbH.
    Copyright © 2021 Xaver Hugl

    Permission is hereby granted, free of charge, to any person obtaining a
    copy of this software and associated documentation files (the "Software"),
    to deal in the Software without restriction, including without limitation
    the rights to use, copy, modify, merge, publish, distribute, sublicense,
    and/or sell copies of the Software, and to permit persons to whom the
    Software is furnished to do so, subject to the following conditions:

    The above copyright notice and this permission notice (including the next
    paragraph) shall be included in all copies or substantial portions of the
    Software.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
    THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
    FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
    DEALINGS IN THE SOFTWARE.
  </copyright>

  <interface name="wp_drm_lease_device_v1" version="1">
    <description summary="lease device">
      This protocol is used by Wayland compositors which act as Direct
      Renderering Manager (DRM) masters to lease DRM resources to Wayland
      clients.

      The compositor will advertise one wp_drm_lease_device_v1 global for each
      DRM node. Some time after a client binds to the wp_drm_lease_device_v1
      global, the compositor will send a drm_fd event followed by zero, one or
      more connector events. After all currently available connectors have been
      sent, the compositor will send a wp_drm_lease_device_v1.done event.

      When the list of connectors available for lease changes the compositor
      will send wp_drm_lease_device_v1.connector events for added connectors and
      wp_drm_lease_connector_v1.withdrawn events for removed connectors,
      followed by a wp_drm_lease_device_v1.done event.

      The compositor will indicate when a device is gone by removing the global
      via a wl_registry.global_remove event. Upon receiving this event, the
      client should destroy any matching wp_drm_lease_device_v1 object.

      To destroy a wp_drm_lease_device_v1 object, the client must first issue
      a release request. Upon receiving this request, the compositor will
      immediately send a released event and destroy the object. The client must
      continue to process and discard drm_fd and connector events until it
      receives the released event. Upon receiving the released event, the
      client can safely cleanup any client-side resources.

      Warning! The protocol described in this file is currently in the testing
      phase. Backward compatible changes may be added together with the
      corresponding interface version bump. Backward incompatible changes can
      only be done by creating a new major version of the extension.
    </description>

    <request name="create_lease_request">
      <description summary="create a lease request object">
        Creates a lease request object.

        See the documentation for wp_drm_lease_request_v1 for details.
      </description>
      <arg name="id" type="new_id" interface="wp_drm_lease_request_v1" />
    </request>

    <request name="release">
      <description summary="release this object">
        Indicates the client no longer wishes to use this object. In response
        the compositor will immediately send the released event and destroy
        this object. It can however not guarantee that the client won't receive
        connector events before the released event. The client must not send any
        requests after this one, doing so will raise a wl_display error.
        Existing connectors, lease request and leases will not be affected.
      </description>
    </request>

    <event name="drm_fd">
      <description summary="open a non-master fd for this DRM node">
        The compositor will send this event when the wp_drm_lease_device_v1
        global is bound, although there are no guarantees as to how long this
        takes - the compositor might need to wait until regaining DRM master.
        The included fd is a non-master DRM file descriptor opened for this
        device and the compositor must not authenticate it.
        The purpose of this event is to give the client the ability to
        query DRM and discover information which may help them pick the
        appropriate DRM device or select the appropriate connectors therein.
      </description>
      <arg name="fd" type="fd" summary="DRM file descriptor" />
    </event>

    <event name="connector">
      <description summary="advertise connectors available for leases">
        The compositor will use this event to advertise connectors available for
        lease by clients. This object may be passed into a lease request to
        indicate the client would like to lease that connector, see
        wp_drm_lease_request_v1.request_connector for details. While the
        compositor will make a best effort to not send disconnected connectors,
        no guarantees can be made.

        The compositor must send the drm_fd event before sending connectors.
        After the drm_fd event it will send all available connectors but may
        send additional connectors at any time.
      </description>
      <arg name="id" type="new_id" interface="wp_drm_lease_connector_v1" />
    </event>

    <event name="done">
      <description summary="signals grouping of connectors">
        The compositor will send this event to indicate that it has sent all
        currently available connectors after the client binds to the global or
        when it updates the connector list, for example on hotplug, drm master
        change or when a leased connector becomes available again. It will
        similarly send this event to group wp_drm_lease_connector_v1.withdrawn
        events of connectors of this device.
      </description>
    </event>

    <event name="released" type="destructor">
      <description summary="the compositor has finished using the device">
        This event is sent in response to the release request and indicates
        that the compositor is done sending connector events.
        The compositor will destroy this object immediately after sending the
        event and it will become invalid. The client should release any
        resources associated with this device after receiving this event.
      </description>
    </event>
  </interface>

  <interface name="wp_drm_lease_connector_v1" version="1">
    <description summary="a leasable DRM connector">
      Represents a DRM connector which is available for lease. These objects are
      created via wp_drm_lease_device_v1.connector events, and should be passed
      to lease requests via wp_drm_lease_request_v1.request_connector.
      Immediately after the wp_drm_lease_connector_v1 object is created the
      compositor will send a name, a description, a connector_id and a done
      event. When the description is updated the compositor will send a
      description event followed by a done event.
    </description>

    <event name="name">
      <description summary="name">
        The compositor sends this event once the connector is created to
        indicate the name of this connector. This will not change for the
        duration of the Wayland session, but is not guaranteed to be consistent
        between sessions.

        If the compositor supports wl_output version 4 and this connector
        corresponds to a wl_output, the compositor should use the same name as
        for the wl_output.
      </description>
      <arg name="name" type="string" summary="connector name" />
    </event>

    <event name="description">
      <description summary="description">
        The compositor sends this event once the connector is created to provide
        a human-readable description for this connector, which may be presented
        to the user. The compositor may send this event multiple times over the
        lifetime of this object to reflect changes in the description.
      </description>
      <arg name="description" type="string" summary="connector description" />
    </event>

    <event name="connector_id">
      <description summary="connector_id">
        The compositor sends this event once the connector is created to
        indicate the DRM object ID which represents the underlying connector
        that is being offered. Note that the final lease may include additional
        object IDs, such as CRTCs and planes.
      </description>
      <arg name="connector_id" type="uint" summary="DRM connector ID" />
    </event>

    <event name="done">
      <description summary="all properties have been sent">
        This event is sent after all properties of a connector have been sent.
        This allows changes to the properties to be seen as atomic even if they
        happen via multiple events.
      </description>
    </event>

    <event name="withdrawn">
      <description summary="lease offer withdrawn">
        Sent to indicate that the compositor will no longer honor requests for
        DRM leases which include this connector. The client may still issue a
        lease request including this connector, but the compositor will send
        wp_drm_lease_v1.finished without issuing a lease fd. Compositors are
        encouraged to send this event when they lose access to connector, for
        example when the connector is hot-unplugged, when the connector gets
        leased to a client or when the compositor loses DRM master.
      </description>
    </event>

    <request name="destroy" type="destructor">
      <description summary="destroy connector">
        The client may send this request to indicate that it will not use this
        connector. Clients are encouraged to send this after receiving the
        "withdrawn" event so that the server can release the resources
        associated with this connector offer. Neither existing lease requests
        nor leases will be affected.
      </description>
    </request>
  </interface>

  <interface name="wp_drm_lease_request_v1" version="1">
    <description summary="DRM lease request">
      A client that wishes to lease DRM resources will attach the list of
      connectors advertised with wp_drm_lease_device_v1.connector that they
      wish to lease, then use wp_drm_lease_request_v1.submit to submit the
      request.
    </description>

    <enum name="error">
      <entry name="wrong_device" value="0"
             summary="requested a connector from a different lease device"/>
      <entry name="duplicate_connector" value="1"
             summary="requested a connector twice"/>
      <entry name="empty_lease" value="2"
             summary="requested a lease without requesting a connector"/>
    </enum>

    <request name="request_connector">
      <description summary="request a connector for this lease">
        Indicates that the client would like to lease the given connector.
        This is only used as a suggestion, the compositor may choose to
        include any resources in the lease it issues, or change the set of
        leased resources at any time. Compositors are however encouraged to
        include the requested connector and other resources necessary
        to drive the connected output in the lease.

        Requesting a connector that was created from a different lease device
        than this lease request raises the wrong_device error. Requesting a
        connector twice will raise the duplicate_connector error.
      </description>
      <arg name="connector" type="object"
           interface="wp_drm_lease_connector_v1" />
    </request>

    <request name="submit" type="destructor">
      <description summary="submit the lease request">
        Submits the lease request and creates a new wp_drm_lease_v1 object.
        After calling submit the compositor will immediately destroy this
        object, issuing any more requests will cause a wl_diplay error.
        The compositor doesn't make any guarantees about the events of the
        lease object, clients cannot expect an immediate response.
        Not requesting any connectors before submitting the lease request
        will raise the empty_lease error.
      </description>
      <arg name="id" type="new_id" interface="wp_drm_lease_v1" />
    </request>
  </interface>

  <interface name="wp_drm_lease_v1" version="1">
    <description summary="a DRM lease">
      A DRM lease object is used to transfer the DRM file descriptor to the
      client and manage the lifetime of the lease.

      Some time after the wp_drm_lease_v1 object is created, the compositor
      will reply with the lease request's result. If the lease request is
      granted, the compositor will send a lease_fd event. If the lease request
      is denied, the compositor will send a finished event without a lease_fd
      event.
    </description>

    <event name="lease_fd">
      <description summary="shares the DRM file descriptor">
        This event returns a file descriptor suitable for use with DRM-related
        ioctls. The client should use drmModeGetLease to enumerate the DRM
        objects which have been leased to them. The compositor guarantees it
        will not use the leased DRM objects itself until it sends the finished
        event. If the compositor cannot or will not grant a lease for the
        requested connectors, it will not send this event, instead sending the
        finished event.

        The compositor will send this event at most once during this objects
        lifetime.
      </description>
      <arg name="leased_fd" type="fd" summary="leased DRM file descriptor" />
    </event>

    <event name="finished">
      <description summary="sent when the lease has been revoked">
        The compositor uses this event to either reject a lease request, or if
        it previously sent a lease_fd, to notify the client that the lease has
        been revoked. If the client requires a new lease, they should destroy
        this object and submit a new lease request. The compositor will send
        no further events for this object after sending the finish event.
        Compositors should revoke the lease when any of the leased resources
        become unavailable, namely when a hot-unplug occurs or when the
        compositor loses DRM master.
      </description>
    </event>

    <request name="destroy" type="destructor">
      <description summary="destroys the lease object">
        The client should send this to indicate that it no longer wishes to use
        this lease. The compositor should use drmModeRevokeLease on the
        appropriate file descriptor, if necessary.
      </description>
    </request>
  </interface>
</protocol>