From: Mikita Lipski <mikita.lip...@amd.com>
Adding PBN attribute to drm_dp_vcpi_allocation structure to
keep track of how much bandwidth each Port requires.
Adding drm_dp_mst_atomic_check_bw_limit to verify that
state's bandwidth needs doesn't exceed available bandwidth.
The funtion is called in drm_dp_mst_atomic_check after
drm_dp_mst_atomic_check_topology_state to fully verify that
the proposed topology is supported.
Cc: Jerry Zuo <jerry....@amd.com>
Cc: Harry Wentland <harry.wentl...@amd.com>
Cc: Lyude Paul <ly...@redhat.com>
Signed-off-by: Mikita Lipski <mikita.lip...@amd.com>
---
drivers/gpu/drm/drm_dp_mst_topology.c | 67 ++++++++++++++++++++++++++-
include/drm/drm_dp_mst_helper.h | 1 +
2 files changed, 66 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c
b/drivers/gpu/drm/drm_dp_mst_topology.c
index 98cc93d5ddd7..5072c1e3dcfe 100644
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -3243,7 +3243,7 @@ int drm_dp_atomic_find_vcpi_slots(struct drm_atomic_state
*state,
{
struct drm_dp_mst_topology_state *topology_state;
struct drm_dp_vcpi_allocation *pos, *vcpi = NULL;
- int prev_slots, req_slots, ret;
+ int prev_slots, prev_bw, req_slots, ret;
topology_state = drm_atomic_get_mst_topology_state(state, mgr);
if (IS_ERR(topology_state))
@@ -3254,6 +3254,7 @@ int drm_dp_atomic_find_vcpi_slots(struct drm_atomic_state
*state,
if (pos->port == port) {
vcpi = pos;
prev_slots = vcpi->vcpi;
+ prev_bw = vcpi->pbn;
/*
* This should never happen, unless the driver tries
@@ -3269,8 +3270,10 @@ int drm_dp_atomic_find_vcpi_slots(struct
drm_atomic_state *state,
break;
}
}
- if (!vcpi)
+ if (!vcpi) {
prev_slots = 0;
+ prev_bw = 0;
+ }
if (pbn_div <= 0)
pbn_div = mgr->pbn_div;
@@ -3280,6 +3283,9 @@ int drm_dp_atomic_find_vcpi_slots(struct drm_atomic_state
*state,
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);
+ DRM_DEBUG_ATOMIC("[CONNECTOR:%d:%s] [MST PORT:%p] PBN %d -> %d\n",
+ port->connector->base.id, port->connector->name,
+ port, prev_bw, pbn);
/* Add the new allocation to the state */
if (!vcpi) {
@@ -3292,6 +3298,7 @@ int drm_dp_atomic_find_vcpi_slots(struct drm_atomic_state
*state,
list_add(&vcpi->next, &topology_state->vcpis);
}
vcpi->vcpi = req_slots;
+ vcpi->pbn = pbn;
ret = req_slots;
return ret;
@@ -3837,6 +3844,59 @@ static void drm_dp_mst_destroy_state(struct
drm_private_obj *obj,
kfree(mst_state);
}
+static bool drm_dp_mst_port_downstream_of_branch(struct drm_dp_mst_port *port,
+ struct drm_dp_mst_branch
*branch)
+{
+ while (port->parent) {
+ if (port->parent == branch)
+ return true;
+
+ if (port->parent->port_parent)
+ port = port->parent->port_parent;
+ else
+ break;
+ }
+ return false;
+}
+
+static inline
+int drm_dp_mst_atomic_check_bw_limit(struct drm_dp_mst_branch *branch,
+ struct drm_dp_mst_topology_state
*mst_state)
+{
+ struct drm_dp_mst_port *port;
+ struct drm_dp_vcpi_allocation *vcpi;
+ int pbn_limit = 0, pbn_used = 0;
+
+ list_for_each_entry(port, &branch->ports, next) {
+ if (port->mstb) {
+ if (drm_dp_mst_atomic_check_bw_limit(port->mstb,
mst_state))
+ return -EINVAL;
+ }
+ if (port->available_pbn > 0)
+ pbn_limit = port->available_pbn;
+ }
+ DRM_DEBUG_ATOMIC("[MST BRANCH:%p] branch has %d PBN available\n",
+ branch,
+ pbn_limit);
+
+ list_for_each_entry(vcpi, &mst_state->vcpis, next) {
+ if (!vcpi->pbn)
+ continue;
+
+ if (drm_dp_mst_port_downstream_of_branch(vcpi->port, branch))
+ pbn_used += vcpi->pbn;
+ }
+ DRM_DEBUG_ATOMIC("[MST BRANCH:%p] branch used %d PBN\n",
+ branch,
+ pbn_used);
+ if (pbn_used > pbn_limit) {
+ DRM_DEBUG_ATOMIC("[MST BRANCH:%p] No available bandwidth\n",
+ branch);
+ return -EINVAL;
+ }
+ return 0;
+}
+
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)
@@ -3968,6 +4028,9 @@ int drm_dp_mst_atomic_check(struct drm_atomic_state
*state)
ret = drm_dp_mst_atomic_check_topology_state(mgr, mst_state);
if (ret)
break;
+ ret = drm_dp_mst_atomic_check_bw_limit(mgr->mst_primary,
mst_state);
+ if (ret)
+ break;
}
return ret;
diff --git a/include/drm/drm_dp_mst_helper.h b/include/drm/drm_dp_mst_helper.h
index b1b00de3083b..5a119a40ed5a 100644
--- a/include/drm/drm_dp_mst_helper.h
+++ b/include/drm/drm_dp_mst_helper.h
@@ -431,6 +431,7 @@ struct drm_dp_payload {
struct drm_dp_vcpi_allocation {
struct drm_dp_mst_port *port;
int vcpi;
+ int pbn;
bool dsc_enabled;
struct list_head next;
};
--
2.17.1
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