Link bandwidth is shared between multiple display streams in DP MST
configurations. The DP MST topology manager structure maintains the shared
link bandwidth for a primary link directly connected to the GPU. For atomic
modesetting drivers, checking if there is sufficient link bandwidth for a
mode needs to be done during the atomic_check phase to avoid failed
modesets. Let's encsapsulate the available link bw information in a state
structure so that bw can be allocated and released atomically for each of
the ports sharing the primary link.
Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@xxxxxxxxx>
---
drivers/gpu/drm/drm_atomic.c | 66 +++++++++++++++++++++++++++++++++++
drivers/gpu/drm/drm_atomic_helper.c | 10 ++++++
drivers/gpu/drm/drm_dp_mst_topology.c | 10 ++++++
include/drm/drm_atomic.h | 13 +++++++
include/drm/drm_dp_mst_helper.h | 13 +++++++
5 files changed, 112 insertions(+)
diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
index 681d5f9..b8e2cea 100644
--- a/drivers/gpu/drm/drm_atomic.c
+++ b/drivers/gpu/drm/drm_atomic.c
@@ -31,6 +31,7 @@
#include <drm/drm_mode.h>
#include <drm/drm_plane_helper.h>
#include <drm/drm_print.h>
+#include <drm/drm_dp_mst_helper.h>
#include <linux/sync_file.h>
#include "drm_crtc_internal.h"
@@ -62,6 +63,7 @@ void drm_atomic_state_default_release(struct drm_atomic_state *state)
kfree(state->connectors);
kfree(state->crtcs);
kfree(state->planes);
+ kfree(state->dp_mst_topologies);
}
EXPORT_SYMBOL(drm_atomic_state_default_release);
@@ -189,6 +191,18 @@ void drm_atomic_state_default_clear(struct drm_atomic_state *state)
state->planes[i].ptr = NULL;
state->planes[i].state = NULL;
}
+
+ for (i = 0; i < state->num_mst_topologies; i++) {
+ struct drm_dp_mst_topology_mgr *mgr = state->dp_mst_topologies[i].ptr;
+
+ if (!mgr)
+ continue;
+
+ kfree(state->dp_mst_topologies[i].state);
+ state->dp_mst_topologies[i].ptr = NULL;
+ state->dp_mst_topologies[i].state = NULL;
+ }
+
}
EXPORT_SYMBOL(drm_atomic_state_default_clear);
@@ -981,6 +995,58 @@ static void drm_atomic_plane_print_state(struct drm_printer *p,
plane->funcs->atomic_print_state(p, state);
}
+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 ret, i;
+ size_t new_size;
+ struct __drm_dp_mst_topology_state *new_arr;
+ struct drm_dp_mst_topology_state *new_mst_state;
+ int num_topologies;
+ struct drm_mode_config *config = &mgr->dev->mode_config;
+
+ WARN_ON(!state->acquire_ctx);
+
+ ret = drm_modeset_lock(&config->connection_mutex, state->acquire_ctx);
+ if (ret)
+ return ERR_PTR(ret);
+
+ for (i = 0; i < state->num_mst_topologies; i++) {
+ if (mgr == state->dp_mst_topologies[i].ptr &&
+ state->dp_mst_topologies[i].state) {
+ return state->dp_mst_topologies[i].state;
+ }
+ }
+
+ num_topologies = state->num_mst_topologies + 1;
+ new_size = sizeof(*state->dp_mst_topologies) * num_topologies;
+ new_arr = krealloc(state->dp_mst_topologies, new_size, GFP_KERNEL);
+ if (!new_arr)
+ return ERR_PTR(-ENOMEM);
+
+ state->dp_mst_topologies = new_arr;
+ memset(&state->dp_mst_topologies[state->num_mst_topologies], 0,
+ sizeof(*state->dp_mst_topologies));
+
+ new_mst_state = kmalloc(sizeof(*mgr->state), GFP_KERNEL);
+ if (!new_mst_state)
+ return ERR_PTR(-ENOMEM);
+
+ new_mst_state->avail_slots = mgr->state->avail_slots;
+ state->dp_mst_topologies[state->num_mst_topologies].state = new_mst_state;
+ state->dp_mst_topologies[state->num_mst_topologies].ptr = mgr;
+ state->num_mst_topologies = num_topologies;
+ new_mst_state->mgr = mgr;
+ mgr->state->state = state;
+
+ DRM_DEBUG_ATOMIC("Added [MST Topology w/ base connector:%d] %p state to %p\n",
+ mgr->conn_base_id, new_mst_state, state);
+
+ return new_mst_state;
+}
+EXPORT_SYMBOL(drm_atomic_get_mst_topology_state);
+
/**
* drm_atomic_get_connector_state - get connector state
* @state: global atomic state object
diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index 5e52244..1cd38b7 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -30,6 +30,7 @@
#include <drm/drm_plane_helper.h>
#include <drm/drm_crtc_helper.h>
#include <drm/drm_atomic_helper.h>
+#include <drm/drm_dp_mst_helper.h>
#include <linux/dma-fence.h>
#include "drm_crtc_internal.h"
@@ -1992,6 +1993,15 @@ void drm_atomic_helper_swap_state(struct drm_atomic_state *state,
connector->state->state = NULL;
}
+ for (i = 0; i < state->num_mst_topologies; i++) {
+ struct drm_dp_mst_topology_mgr *mgr;
+
+ mgr = state->dp_mst_topologies[i].ptr;
+ mgr->state->state = state;
+ swap(state->dp_mst_topologies[i].state, mgr->state);
+ mgr->state->state = NULL;
+ }
+
for_each_crtc_in_state(state, crtc, crtc_state, i) {
crtc->state->state = state;
swap(state->crtcs[i].state, crtc->state);
diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
index d42a6c0..1be19e1 100644
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -2042,6 +2042,9 @@ int drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr *mgr, bool ms
goto out_unlock;
}
+ /* max. time slots - one slot for MTP header */
+ mgr->state->avail_slots = 63;
+
/* add initial branch device at LCT 1 */
mstb = drm_dp_add_mst_branch_device(1, NULL);
if (mstb == NULL) {
@@ -2973,6 +2976,11 @@ int drm_dp_mst_topology_mgr_init(struct drm_dp_mst_topology_mgr *mgr,
mgr->proposed_vcpis = kcalloc(max_payloads, sizeof(struct drm_dp_vcpi *), GFP_KERNEL);
if (!mgr->proposed_vcpis)
return -ENOMEM;
+ mgr->state = kzalloc(sizeof(*mgr->state), GFP_KERNEL);
+ if (!mgr->state)
+ return -ENOMEM;
+ mgr->state->mgr = mgr;
+
set_bit(0, &mgr->payload_mask);
if (test_calc_pbn_mode() < 0)
DRM_ERROR("MST PBN self-test failed\n");
@@ -2995,6 +3003,8 @@ void drm_dp_mst_topology_mgr_destroy(struct drm_dp_mst_topology_mgr *mgr)
kfree(mgr->proposed_vcpis);
mgr->proposed_vcpis = NULL;
mutex_unlock(&mgr->payload_lock);
+ kfree(mgr->state);
+ mgr->state = NULL;
mgr->dev = NULL;
mgr->aux = NULL;
}
diff --git a/include/drm/drm_atomic.h b/include/drm/drm_atomic.h
index fd2d971..7ac5ed6 100644
--- a/include/drm/drm_atomic.h
+++ b/include/drm/drm_atomic.h
@@ -153,6 +153,11 @@ struct __drm_connnectors_state {
struct drm_connector_state *state;
};
+struct __drm_dp_mst_topology_state {
+ struct drm_dp_mst_topology_mgr *ptr;
+ struct drm_dp_mst_topology_state *state;
+};
+
/**
* struct drm_atomic_state - the global state object for atomic updates
* @ref: count of all references to this state (will not be freed until zero)
@@ -164,6 +169,8 @@ struct __drm_connnectors_state {
* @crtcs: pointer to array of CRTC pointers
* @num_connector: size of the @connectors and @connector_states arrays
* @connectors: pointer to array of structures with per-connector data
+ * @num_mst_topologies: size of the @dp_mst_topologies array
+ * @dp_mst_topologies: pointer to array of structures with per-MST topology manager data
* @acquire_ctx: acquire context for this atomic modeset state update
*/
struct drm_atomic_state {
@@ -177,6 +184,8 @@ struct drm_atomic_state {
struct __drm_crtcs_state *crtcs;
int num_connector;
struct __drm_connnectors_state *connectors;
+ int num_mst_topologies;
+ struct __drm_dp_mst_topology_state *dp_mst_topologies;
struct drm_modeset_acquire_ctx *acquire_ctx;
@@ -250,6 +259,10 @@ int drm_atomic_connector_set_property(struct drm_connector *connector,
struct drm_connector_state *state, struct drm_property *property,
uint64_t val);
+struct drm_dp_mst_topology_state * __must_check
+drm_atomic_get_mst_topology_state(struct drm_atomic_state *state,
+ struct drm_dp_mst_topology_mgr *mgr);
+
/**
* drm_atomic_get_existing_crtc_state - get crtc state, if it exists
* @state: global atomic state object
diff --git a/include/drm/drm_dp_mst_helper.h b/include/drm/drm_dp_mst_helper.h
index 98d3c73..0a9bf20 100644
--- a/include/drm/drm_dp_mst_helper.h
+++ b/include/drm/drm_dp_mst_helper.h
@@ -403,6 +403,12 @@ struct drm_dp_payload {
int vcpi;
};
+struct drm_dp_mst_topology_state {
+ int avail_slots;
+ struct drm_atomic_state *state;
+ struct drm_dp_mst_topology_mgr *mgr;
+};
+
/**
* struct drm_dp_mst_topology_mgr - DisplayPort MST manager
*
@@ -481,6 +487,11 @@ struct drm_dp_mst_topology_mgr {
int pbn_div;
/**
+ * @state: MST topology manager state for atomic modesetting drivers
+ */
+ struct drm_dp_mst_topology_state *state;
+
+ /**
* @qlock: protects @tx_msg_downq, the tx_slots in struct
* &drm_dp_mst_branch and txmsg->state once they are queued
*/
@@ -596,4 +607,6 @@ void drm_dp_mst_dump_topology(struct seq_file *m,
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);
#endif
--
2.7.4
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