The avail_slots member in the MST topology manager is never updated to
reflect the available vcpi slots. The check is effectively against
total_slots. So, let's make that check obvious. Secondly, since the total
vcpi time slots is always 63 and does not depend on the link BW, remove
total_slots from MST topology manager struct. The third change is to
remove total_pbn which is hardcoded to 2560. The total PBN that the
topology manager allocates from depends on the link rate and is not a
constant. So, fix this by removing the total_pbn member itself. Finally,
make debug messages more descriptive.

Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandi...@intel.com>
---
 drivers/gpu/drm/drm_dp_mst_topology.c | 16 ++++++++--------
 include/drm/drm_dp_mst_helper.h       | 12 ------------
 2 files changed, 8 insertions(+), 20 deletions(-)

diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c 
b/drivers/gpu/drm/drm_dp_mst_topology.c
index 122a1b0..d9edd84 100644
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -2042,10 +2042,6 @@ int drm_dp_mst_topology_mgr_set_mst(struct 
drm_dp_mst_topology_mgr *mgr, bool ms
                        goto out_unlock;
                }
 
-               mgr->total_pbn = 2560;
-               mgr->total_slots = DIV_ROUND_UP(mgr->total_pbn, mgr->pbn_div);
-               mgr->avail_slots = mgr->total_slots;
-
                /* add initial branch device at LCT 1 */
                mstb = drm_dp_add_mst_branch_device(1, NULL);
                if (mstb == NULL) {
@@ -2475,7 +2471,8 @@ int drm_dp_find_vcpi_slots(struct drm_dp_mst_topology_mgr 
*mgr,
 
        num_slots = DIV_ROUND_UP(pbn, mgr->pbn_div);
 
-       if (num_slots > mgr->avail_slots)
+       /* max. time slots - one slot for MTP header */
+       if (num_slots > 63)
                return -ENOSPC;
        return num_slots;
 }
@@ -2489,7 +2486,8 @@ static int drm_dp_init_vcpi(struct 
drm_dp_mst_topology_mgr *mgr,
 
        num_slots = DIV_ROUND_UP(pbn, mgr->pbn_div);
 
-       if (num_slots > mgr->avail_slots)
+       /* max. time slots - one slot for MTP header */
+       if (num_slots > 63)
                return -ENOSPC;
 
        vcpi->pbn = pbn;
@@ -2528,10 +2526,12 @@ bool drm_dp_mst_allocate_vcpi(struct 
drm_dp_mst_topology_mgr *mgr, struct drm_dp
 
        ret = drm_dp_init_vcpi(mgr, &port->vcpi, pbn);
        if (ret) {
-               DRM_DEBUG_KMS("failed to init vcpi %d %d %d\n", 
DIV_ROUND_UP(pbn, mgr->pbn_div), mgr->avail_slots, ret);
+               DRM_DEBUG_KMS("failed to init vcpi slots=%d max=63 ret=%d\n",
+                               DIV_ROUND_UP(pbn, mgr->pbn_div), ret);
                goto out;
        }
-       DRM_DEBUG_KMS("initing vcpi for %d %d\n", pbn, port->vcpi.num_slots);
+       DRM_DEBUG_KMS("initing vcpi for pbn=%d slots=%d\n",
+                       pbn, port->vcpi.num_slots);
        *slots = port->vcpi.num_slots;
 
        drm_dp_put_port(port);
diff --git a/include/drm/drm_dp_mst_helper.h b/include/drm/drm_dp_mst_helper.h
index 27f3e99..b0f4a09 100644
--- a/include/drm/drm_dp_mst_helper.h
+++ b/include/drm/drm_dp_mst_helper.h
@@ -479,18 +479,6 @@ struct drm_dp_mst_topology_mgr {
         * @pbn_div: PBN to slots divisor.
         */
        int pbn_div;
-       /**
-        * @total_slots: Total slots that can be allocated.
-        */
-       int total_slots;
-       /**
-        * @avail_slots: Still available slots that can be allocated.
-        */
-       int avail_slots;
-       /**
-        * @total_pbn: Total PBN count.
-        */
-       int total_pbn;
 
        /**
         * @qlock: protects @tx_msg_downq, the tx_slots in struct
-- 
2.7.4

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