On Tue, Jan 08, 2019 at 07:35:15PM -0500, Lyude Paul wrote:
> There has been a TODO waiting for quite a long time in
> drm_dp_mst_topology.c:
>
> /* We cannot rely on port->vcpi.num_slots to update
> * topology_state->avail_slots as the port may not exist if the parent
> * branch device was unplugged. This should be fixed by tracking
> * per-port slot allocation in drm_dp_mst_topology_state instead of
> * depending on the caller to tell us how many slots to release.
> */
>
> That's not the only reason we should fix this: forcing the driver to
> track the VCPI allocations throughout a state's atomic check is
> error prone, because it means that extra care has to be taken with the
> order that drm_dp_atomic_find_vcpi_slots() and
> drm_dp_atomic_release_vcpi_slots() are called in in order to ensure
> idempotency. Currently the only driver actually using these helpers,
> i915, doesn't even do this correctly: multiple ->best_encoder() checks
> with i915's current implementation would not be idempotent and would
> over-allocate VCPI slots, something I learned trying to implement
> fallback retraining in MST.
>
> So: simplify this whole mess, and teach drm_dp_atomic_find_vcpi_slots()
> and drm_dp_atomic_release_vcpi_slots() to track the VCPI allocations for
> each port. This allows us to ensure idempotency without having to rely
> on the driver as much. Additionally: the driver doesn't need to do any
> kind of VCPI slot tracking anymore if it doesn't need it for it's own
> internal state.
>
> Additionally; this adds a new drm_dp_mst_atomic_check() helper which
> must be used by atomic drivers to perform validity checks for the new
> VCPI allocations incurred by a state.
>
> Also: update the documentation and make it more obvious that these
> /must/ be called by /all/ atomic drivers supporting MST.
>
> Changes since v9:
> * Add some missing changes that were requested by danvet that I forgot
> about after I redid all of the kref stuff:
> * Remove unnecessary state changes in intel_dp_mst_atomic_check
> * Cleanup atomic check logic for VCPI allocations - all we need to check in
> compute_config is whether or not this state disables a CRTC, then free
> VCPI based off that
>
> Changes since v8:
> * Fix compile errors, whoops!
>
> Changes since v7:
> - Don't check for mixed stale/valid VCPI allocations, just rely on
> connector registration to stop such erroneous modesets
>
> Changes since v6:
> - Keep a kref to all of the ports we have allocations on. This required
> a good bit of changing to when we call drm_dp_find_vcpi_slots(),
> mainly that we need to ensure that we only redo VCPI allocations on
> actual mode or CRTC changes, not crtc_state->active changes.
> Additionally, we no longer take the registration of the DRM connector
> for each port into account because so long as we have a kref to the
> port in the new or previous atomic state, the connector will stay
> registered.
> - Use the small changes to drm_dp_put_port() to add even more error
> checking to make misusage of the helpers more obvious. I added this
> after having to chase down various use-after-free conditions that
> started popping up from the new helpers so no one else has to
> troubleshoot that.
> - Move some accidental DRM_DEBUG_KMS() calls to DRM_DEBUG_ATOMIC()
> - Update documentation again, note that find/release() should both not be
> called on the same port in a single atomic check phase (but multiple
> calls to one or the other is OK)
>
> Changes since v4:
> - Don't skip the atomic checks for VCPI allocations if no new VCPI
> allocations happen in a state. This makes the next change I'm about
> to list here a lot easier to implement.
> - Don't ignore VCPI allocations on destroyed ports, instead ensure that
> when ports are destroyed and still have VCPI allocations in the
> topology state, the only state changes allowed are releasing said
> ports' VCPI. This prevents a state with a mix of VCPI allocations
> from destroyed ports, and allocations from valid ports.
>
> Changes since v3:
> - Don't release VCPI allocations in the topology state immediately in
> drm_dp_atomic_release_vcpi_slots(), instead mark them as 0 and skip
> over them in drm_dp_mst_duplicate_state(). This makes it so
> drm_dp_atomic_release_vcpi_slots() is still idempotent while also
> throwing warnings if the driver messes up it's book keeping and tries
> to release VCPI slots on a port that doesn't have any pre-existing
> VCPI allocation - danvet
> - Change mst_state/state in some debugging messages to "mst state"
>
> Changes since v2:
> - Use kmemdup() for duplicating MST state - danvet
> - Move port validation out of duplicate state callback - danvet
> - Handle looping through MST topology states in
> drm_dp_mst_atomic_check() so the driver doesn't have to do it
> - Fix documentation in drm_dp_atomic_find_vcpi_slots()
> - Move the atomic check for each individual topology state into it's
> own function, reduces indenting
> - Don't consider "stale" MST ports when calculating the bandwidth
> requirements. This is needed because originally we relied on the
> state duplication functions to prune any stale ports from the new
> state, which would prevent us from incorrectly considering their
> bandwidth requirements alongside legitimate new payloads.
> - Add function references in drm_dp_atomic_release_vcpi_slots() - danvet
> - Annotate atomic VCPI and atomic check functions with __must_check
> - danvet
>
> Changes since v1:
> - Don't use the now-removed ->atomic_check() for private objects hook,
> just give drivers a function to call themselves
>
> Signed-off-by: Lyude Paul <lyude@xxxxxxxxxx>
> Cc: Daniel Vetter <daniel.vetter@xxxxxxxx>
> Cc: David Airlie <airlied@xxxxxxxxxx>
> Cc: Jerry Zuo <Jerry.Zuo@xxxxxxx>
> Cc: Harry Wentland <harry.wentland@xxxxxxx>
> Cc: Juston Li <juston.li@xxxxxxxxx>
Reviewed-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
> ---
> drivers/gpu/drm/drm_dp_mst_topology.c | 247 ++++++++++++++++++++++----
> drivers/gpu/drm/i915/intel_display.c | 4 +
> drivers/gpu/drm/i915/intel_dp_mst.c | 54 +++---
> include/drm/drm_dp_mst_helper.h | 23 ++-
> 4 files changed, 266 insertions(+), 62 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
> index 370371145cdd..fc778c6d487e 100644
> --- a/drivers/gpu/drm/drm_dp_mst_topology.c
> +++ b/drivers/gpu/drm/drm_dp_mst_topology.c
> @@ -3020,21 +3020,42 @@ static int drm_dp_init_vcpi(struct drm_dp_mst_topology_mgr *mgr,
> }
>
> /**
> - * drm_dp_atomic_find_vcpi_slots() - Find and add vcpi slots to the state
> + * drm_dp_atomic_find_vcpi_slots() - Find and add VCPI slots to the state
> * @state: global atomic state
> * @mgr: MST topology manager for the port
> * @port: port to find vcpi slots for
> * @pbn: bandwidth required for the mode in PBN
> *
> - * RETURNS:
> - * Total slots in the atomic state assigned for this port or error
> + * Allocates VCPI slots to @port, replacing any previous VCPI allocations it
> + * may have had. Any atomic drivers which support MST must call this function
> + * in their &drm_encoder_helper_funcs.atomic_check() callback to change the
> + * current VCPI allocation for the new state, but only when
> + * &drm_crtc_state.mode_changed or &drm_crtc_state.connectors_changed is set
> + * to ensure compatibility with userspace applications that still use the
> + * legacy modesetting UAPI.
> + *
> + * Allocations set by this function are not checked against the bandwidth
> + * restraints of @mgr until the driver calls drm_dp_mst_atomic_check().
> + *
> + * Additionally, it is OK to call this function multiple times on the same
> + * @port as needed. It is not OK however, to call this function and
> + * drm_dp_atomic_release_vcpi_slots() in the same atomic check phase.
> + *
> + * See also:
> + * drm_dp_atomic_release_vcpi_slots()
> + * drm_dp_mst_atomic_check()
> + *
> + * Returns:
> + * Total slots in the atomic state assigned for this port, or a negative error
> + * code if the port no longer exists
> */
> int drm_dp_atomic_find_vcpi_slots(struct drm_atomic_state *state,
> struct drm_dp_mst_topology_mgr *mgr,
> struct drm_dp_mst_port *port, int pbn)
> {
> struct drm_dp_mst_topology_state *topology_state;
> - int req_slots;
> + struct drm_dp_vcpi_allocation *pos, *vcpi = NULL;
> + int prev_slots, req_slots, ret;
>
> topology_state = drm_atomic_get_mst_topology_state(state, mgr);
> if (IS_ERR(topology_state))
> @@ -3043,20 +3064,54 @@ int drm_dp_atomic_find_vcpi_slots(struct drm_atomic_state *state,
> port = drm_dp_mst_topology_get_port_validated(mgr, port);
> if (port == NULL)
> return -EINVAL;
> - req_slots = DIV_ROUND_UP(pbn, mgr->pbn_div);
> - DRM_DEBUG_KMS("vcpi slots req=%d, avail=%d\n",
> - req_slots, topology_state->avail_slots);
>
> - if (req_slots > topology_state->avail_slots) {
> - drm_dp_mst_topology_put_port(port);
> - return -ENOSPC;
> + /* Find the current allocation for this port, if any */
> + list_for_each_entry(pos, &topology_state->vcpis, next) {
> + if (pos->port == port) {
> + vcpi = pos;
> + prev_slots = vcpi->vcpi;
> +
> + /*
> + * This should never happen, unless the driver tries
> + * releasing and allocating the same VCPI allocation,
> + * which is an error
> + */
> + if (WARN_ON(!prev_slots)) {
> + DRM_ERROR("cannot allocate and release VCPI on [MST PORT:%p] in the same state\n",
> + port);
> + return -EINVAL;
> + }
> +
> + break;
> + }
> }
> + if (!vcpi)
> + prev_slots = 0;
> +
> + req_slots = DIV_ROUND_UP(pbn, mgr->pbn_div);
> +
> + DRM_DEBUG_ATOMIC("[CONNECTOR:%d:%s] [MST PORT:%p] VCPI %d -> %d\n",
> + port->connector->base.id, port->connector->name,
> + port, prev_slots, req_slots);
> +
> + /* Add the new allocation to the state */
> + if (!vcpi) {
> + vcpi = kzalloc(sizeof(*vcpi), GFP_KERNEL);
> + if (!vcpi) {
> + ret = -ENOMEM;
> + goto out;
> + }
>
> - topology_state->avail_slots -= req_slots;
> - DRM_DEBUG_KMS("vcpi slots avail=%d", topology_state->avail_slots);
> + drm_dp_mst_get_port_malloc(port);
> + vcpi->port = port;
> + list_add(&vcpi->next, &topology_state->vcpis);
> + }
> + vcpi->vcpi = req_slots;
>
> + ret = req_slots;
> +out:
> drm_dp_mst_topology_put_port(port);
> - return req_slots;
> + return ret;
> }
> EXPORT_SYMBOL(drm_dp_atomic_find_vcpi_slots);
>
> @@ -3064,31 +3119,57 @@ EXPORT_SYMBOL(drm_dp_atomic_find_vcpi_slots);
> * drm_dp_atomic_release_vcpi_slots() - Release allocated vcpi slots
> * @state: global atomic state
> * @mgr: MST topology manager for the port
> - * @slots: number of vcpi slots to release
> + * @port: The port to release the VCPI slots from
> *
> - * RETURNS:
> - * 0 if @slots were added back to &drm_dp_mst_topology_state->avail_slots or
> - * negative error code
> + * Releases any VCPI slots that have been allocated to a port in the atomic
> + * state. Any atomic drivers which support MST must call this function in
> + * their &drm_connector_helper_funcs.atomic_check() callback when the
> + * connector will no longer have VCPI allocated (e.g. because it's CRTC was
> + * removed) when it had VCPI allocated in the previous atomic state.
> + *
> + * It is OK to call this even if @port has been removed from the system.
> + * Additionally, it is OK to call this function multiple times on the same
> + * @port as needed. It is not OK however, to call this function and
> + * drm_dp_atomic_find_vcpi_slots() on the same @port in a single atomic check
> + * phase.
> + *
> + * See also:
> + * drm_dp_atomic_find_vcpi_slots()
> + * drm_dp_mst_atomic_check()
> + *
> + * Returns:
> + * 0 if all slots for this port were added back to
> + * &drm_dp_mst_topology_state.avail_slots or negative error code
> */
> int drm_dp_atomic_release_vcpi_slots(struct drm_atomic_state *state,
> struct drm_dp_mst_topology_mgr *mgr,
> - int slots)
> + struct drm_dp_mst_port *port)
> {
> struct drm_dp_mst_topology_state *topology_state;
> + struct drm_dp_vcpi_allocation *pos;
> + bool found = false;
>
> topology_state = drm_atomic_get_mst_topology_state(state, mgr);
> if (IS_ERR(topology_state))
> return PTR_ERR(topology_state);
>
> - /* We cannot rely on port->vcpi.num_slots to update
> - * topology_state->avail_slots as the port may not exist if the parent
> - * branch device was unplugged. This should be fixed by tracking
> - * per-port slot allocation in drm_dp_mst_topology_state instead of
> - * depending on the caller to tell us how many slots to release.
> - */
> - topology_state->avail_slots += slots;
> - DRM_DEBUG_KMS("vcpi slots released=%d, avail=%d\n",
> - slots, topology_state->avail_slots);
> + list_for_each_entry(pos, &topology_state->vcpis, next) {
> + if (pos->port == port) {
> + found = true;
> + break;
> + }
> + }
> + if (WARN_ON(!found)) {
> + DRM_ERROR("no VCPI for [MST PORT:%p] found in mst state %p\n",
> + port, &topology_state->base);
> + return -EINVAL;
> + }
> +
> + DRM_DEBUG_ATOMIC("[MST PORT:%p] VCPI %d -> 0\n", port, pos->vcpi);
> + if (pos->vcpi) {
> + drm_dp_mst_put_port_malloc(port);
> + pos->vcpi = 0;
> + }
>
> return 0;
> }
> @@ -3510,15 +3591,41 @@ static void drm_dp_destroy_connector_work(struct work_struct *work)
> static struct drm_private_state *
> drm_dp_mst_duplicate_state(struct drm_private_obj *obj)
> {
> - struct drm_dp_mst_topology_state *state;
> + struct drm_dp_mst_topology_state *state, *old_state =
> + to_dp_mst_topology_state(obj->state);
> + struct drm_dp_vcpi_allocation *pos, *vcpi;
>
> - state = kmemdup(obj->state, sizeof(*state), GFP_KERNEL);
> + state = kmemdup(old_state, sizeof(*state), GFP_KERNEL);
> if (!state)
> return NULL;
>
> __drm_atomic_helper_private_obj_duplicate_state(obj, &state->base);
>
> + INIT_LIST_HEAD(&state->vcpis);
> +
> + list_for_each_entry(pos, &old_state->vcpis, next) {
> + /* Prune leftover freed VCPI allocations */
> + if (!pos->vcpi)
> + continue;
> +
> + vcpi = kmemdup(pos, sizeof(*vcpi), GFP_KERNEL);
> + if (!vcpi)
> + goto fail;
> +
> + drm_dp_mst_get_port_malloc(vcpi->port);
> + list_add(&vcpi->next, &state->vcpis);
> + }
> +
> return &state->base;
> +
> +fail:
> + list_for_each_entry_safe(pos, vcpi, &state->vcpis, next) {
> + drm_dp_mst_put_port_malloc(pos->port);
> + kfree(pos);
> + }
> + kfree(state);
> +
> + return NULL;
> }
>
> static void drm_dp_mst_destroy_state(struct drm_private_obj *obj,
> @@ -3526,10 +3633,88 @@ static void drm_dp_mst_destroy_state(struct drm_private_obj *obj,
> {
> struct drm_dp_mst_topology_state *mst_state =
> to_dp_mst_topology_state(state);
> + struct drm_dp_vcpi_allocation *pos, *tmp;
> +
> + list_for_each_entry_safe(pos, tmp, &mst_state->vcpis, next) {
> + /* We only keep references to ports with non-zero VCPIs */
> + if (pos->vcpi)
> + drm_dp_mst_put_port_malloc(pos->port);
> + kfree(pos);
> + }
>
> kfree(mst_state);
> }
>
> +static inline int
> +drm_dp_mst_atomic_check_topology_state(struct drm_dp_mst_topology_mgr *mgr,
> + struct drm_dp_mst_topology_state *mst_state)
> +{
> + struct drm_dp_vcpi_allocation *vcpi;
> + int avail_slots = 63;
> +
> + list_for_each_entry(vcpi, &mst_state->vcpis, next) {
> + /* Releasing VCPI is always OK-even if the port is gone */
> + if (!vcpi->vcpi) {
> + DRM_DEBUG_ATOMIC("[MST PORT:%p] releases all VCPI slots\n",
> + vcpi->port);
> + continue;
> + }
> +
> + DRM_DEBUG_ATOMIC("[MST PORT:%p] requires %d vcpi slots\n",
> + vcpi->port, vcpi->vcpi);
> +
> + avail_slots -= vcpi->vcpi;
> + if (avail_slots < 0) {
> + DRM_DEBUG_ATOMIC("[MST PORT:%p] not enough VCPI slots in mst state %p (avail=%d)\n",
> + vcpi->port, mst_state,
> + avail_slots + vcpi->vcpi);
> + return -ENOSPC;
> + }
> + }
> + DRM_DEBUG_ATOMIC("[MST MGR:%p] mst state %p VCPI avail=%d used=%d\n",
> + mgr, mst_state, avail_slots,
> + 63 - avail_slots);
> +
> + return 0;
> +}
> +
> +/**
> + * drm_dp_mst_atomic_check - Check that the new state of an MST topology in an
> + * atomic update is valid
> + * @state: Pointer to the new &struct drm_dp_mst_topology_state
> + *
> + * Checks the given topology state for an atomic update to ensure that it's
> + * valid. This includes checking whether there's enough bandwidth to support
> + * the new VCPI allocations in the atomic update.
> + *
> + * Any atomic drivers supporting DP MST must make sure to call this after
> + * checking the rest of their state in their
> + * &drm_mode_config_funcs.atomic_check() callback.
> + *
> + * See also:
> + * drm_dp_atomic_find_vcpi_slots()
> + * drm_dp_atomic_release_vcpi_slots()
> + *
> + * Returns:
> + *
> + * 0 if the new state is valid, negative error code otherwise.
> + */
> +int drm_dp_mst_atomic_check(struct drm_atomic_state *state)
> +{
> + struct drm_dp_mst_topology_mgr *mgr;
> + struct drm_dp_mst_topology_state *mst_state;
> + int i, ret = 0;
> +
> + for_each_new_mst_mgr_in_state(state, mgr, mst_state, i) {
> + ret = drm_dp_mst_atomic_check_topology_state(mgr, mst_state);
> + if (ret)
> + break;
> + }
> +
> + return ret;
> +}
> +EXPORT_SYMBOL(drm_dp_mst_atomic_check);
> +
> const struct drm_private_state_funcs drm_dp_mst_topology_state_funcs = {
> .atomic_duplicate_state = drm_dp_mst_duplicate_state,
> .atomic_destroy_state = drm_dp_mst_destroy_state,
> @@ -3612,9 +3797,7 @@ int drm_dp_mst_topology_mgr_init(struct drm_dp_mst_topology_mgr *mgr,
> return -ENOMEM;
>
> mst_state->mgr = mgr;
> -
> - /* max. time slots - one slot for MTP header */
> - mst_state->avail_slots = 63;
> + INIT_LIST_HEAD(&mst_state->vcpis);
>
> drm_atomic_private_obj_init(dev, &mgr->base,
> &mst_state->base,
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 696e6f5680df..d1595be4a880 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -12710,6 +12710,10 @@ static int intel_atomic_check(struct drm_device *dev,
> "[modeset]" : "[fastset]");
> }
>
> + ret = drm_dp_mst_atomic_check(state);
> + if (ret)
> + return ret;
> +
> if (any_ms) {
> ret = intel_modeset_checks(state);
>
> diff --git a/drivers/gpu/drm/i915/intel_dp_mst.c b/drivers/gpu/drm/i915/intel_dp_mst.c
> index 631fd1537252..c8e2215628e6 100644
> --- a/drivers/gpu/drm/i915/intel_dp_mst.c
> +++ b/drivers/gpu/drm/i915/intel_dp_mst.c
> @@ -41,8 +41,12 @@ static bool intel_dp_mst_compute_config(struct intel_encoder *encoder,
> struct drm_connector *connector = conn_state->connector;
> void *port = to_intel_connector(connector)->port;
> struct drm_atomic_state *state = pipe_config->base.state;
> + struct drm_crtc *crtc = pipe_config->base.crtc;
> + struct drm_crtc_state *old_crtc_state =
> + drm_atomic_get_old_crtc_state(state, crtc);
> int bpp;
> - int lane_count, slots = 0;
> + int lane_count, slots =
> + to_intel_crtc_state(old_crtc_state)->dp_m_n.tu;
> const struct drm_display_mode *adjusted_mode = &pipe_config->base.adjusted_mode;
> int mst_pbn;
> bool constant_n = drm_dp_has_quirk(&intel_dp->desc,
> @@ -107,35 +111,39 @@ static bool intel_dp_mst_compute_config(struct intel_encoder *encoder,
> return true;
> }
>
> -static int intel_dp_mst_atomic_check(struct drm_connector *connector,
> - struct drm_connector_state *new_conn_state)
> +static int
> +intel_dp_mst_atomic_check(struct drm_connector *connector,
> + struct drm_connector_state *new_conn_state)
> {
> struct drm_atomic_state *state = new_conn_state->state;
> - struct drm_connector_state *old_conn_state;
> - struct drm_crtc *old_crtc;
> + struct drm_connector_state *old_conn_state =
> + drm_atomic_get_old_connector_state(state, connector);
> + struct intel_connector *intel_connector =
> + to_intel_connector(connector);
> + struct drm_crtc *new_crtc = new_conn_state->crtc;
> struct drm_crtc_state *crtc_state;
> - int slots, ret = 0;
> + struct drm_dp_mst_topology_mgr *mgr;
> + int ret = 0;
>
> - old_conn_state = drm_atomic_get_old_connector_state(state, connector);
> - old_crtc = old_conn_state->crtc;
> - if (!old_crtc)
> - return ret;
> -
> - crtc_state = drm_atomic_get_new_crtc_state(state, old_crtc);
> - slots = to_intel_crtc_state(crtc_state)->dp_m_n.tu;
> - if (drm_atomic_crtc_needs_modeset(crtc_state) && slots > 0) {
> - struct drm_dp_mst_topology_mgr *mgr;
> - struct drm_encoder *old_encoder;
> + if (!old_conn_state->crtc)
> + return 0;
>
> - old_encoder = old_conn_state->best_encoder;
> - mgr = &enc_to_mst(old_encoder)->primary->dp.mst_mgr;
> + /* We only want to free VCPI if this state disables the CRTC on this
> + * connector
> + */
> + if (new_crtc) {
> + crtc_state = drm_atomic_get_new_crtc_state(state, new_crtc);
>
> - ret = drm_dp_atomic_release_vcpi_slots(state, mgr, slots);
> - if (ret)
> - DRM_DEBUG_KMS("failed releasing %d vcpi slots:%d\n", slots, ret);
> - else
> - to_intel_crtc_state(crtc_state)->dp_m_n.tu = 0;
> + if (!crtc_state ||
> + !drm_atomic_crtc_needs_modeset(crtc_state) ||
> + crtc_state->enable)
> + return 0;
> }
> +
> + mgr = &enc_to_mst(old_conn_state->best_encoder)->primary->dp.mst_mgr;
> + ret = drm_dp_atomic_release_vcpi_slots(state, mgr,
> + intel_connector->port);
> +
> return ret;
> }
>
> diff --git a/include/drm/drm_dp_mst_helper.h b/include/drm/drm_dp_mst_helper.h
> index 581163c8d7d7..451d020f0137 100644
> --- a/include/drm/drm_dp_mst_helper.h
> +++ b/include/drm/drm_dp_mst_helper.h
> @@ -425,9 +425,15 @@ struct drm_dp_payload {
>
> #define to_dp_mst_topology_state(x) container_of(x, struct drm_dp_mst_topology_state, base)
>
> +struct drm_dp_vcpi_allocation {
> + struct drm_dp_mst_port *port;
> + int vcpi;
> + struct list_head next;
> +};
> +
> struct drm_dp_mst_topology_state {
> struct drm_private_state base;
> - int avail_slots;
> + struct list_head vcpis;
> struct drm_dp_mst_topology_mgr *mgr;
> };
>
> @@ -638,14 +644,17 @@ void drm_dp_mst_topology_mgr_suspend(struct drm_dp_mst_topology_mgr *mgr);
> int drm_dp_mst_topology_mgr_resume(struct drm_dp_mst_topology_mgr *mgr);
> struct drm_dp_mst_topology_state *drm_atomic_get_mst_topology_state(struct drm_atomic_state *state,
> struct drm_dp_mst_topology_mgr *mgr);
> -int drm_dp_atomic_find_vcpi_slots(struct drm_atomic_state *state,
> - struct drm_dp_mst_topology_mgr *mgr,
> - struct drm_dp_mst_port *port, int pbn);
> -int drm_dp_atomic_release_vcpi_slots(struct drm_atomic_state *state,
> - struct drm_dp_mst_topology_mgr *mgr,
> - int slots);
> +int __must_check
> +drm_dp_atomic_find_vcpi_slots(struct drm_atomic_state *state,
> + struct drm_dp_mst_topology_mgr *mgr,
> + struct drm_dp_mst_port *port, int pbn);
> +int __must_check
> +drm_dp_atomic_release_vcpi_slots(struct drm_atomic_state *state,
> + struct drm_dp_mst_topology_mgr *mgr,
> + struct drm_dp_mst_port *port);
> int drm_dp_send_power_updown_phy(struct drm_dp_mst_topology_mgr *mgr,
> struct drm_dp_mst_port *port, bool power_up);
> +int __must_check drm_dp_mst_atomic_check(struct drm_atomic_state *state);
>
> void drm_dp_mst_get_port_malloc(struct drm_dp_mst_port *port);
> void drm_dp_mst_put_port_malloc(struct drm_dp_mst_port *port);
> --
> 2.20.1
>
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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