On 2021-10-13 12:09 p.m., Jani Nikula wrote:
I believe that was the original structure but, lyude recommended to put them into the same patch to see how it is being usedOn Tue, 12 Oct 2021, Bhawanpreet Lakha <Bhawanpreet.Lakha@xxxxxxx> wrote:8b/10b encoding format requires to reserve the first slot for recording metadata. Real data transmission starts from the second slot, with a total of available 63 slots available. In 128b/132b encoding format, metadata is transmitted separately in LLCP packet before MTP. Real data transmission starts from the first slot, with a total of 64 slots available. v2: * Remove get_mst_link_encoding_cap * Move total/start slots to mst_state, and copy it to mst_mgr in atomic_check Signed-off-by: Fangzhi Zuo <Jerry.Zuo@xxxxxxx> Signed-off-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@xxxxxxx> --- .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 28 +++++++++++++++ drivers/gpu/drm/drm_dp_mst_topology.c | 35 +++++++++++++++---- include/drm/drm_dp_mst_helper.h | 13 +++++++ 3 files changed, 69 insertions(+), 7 deletions(-) diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c index 5020f2d36fe1..4ad50eb0091a 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c @@ -10612,6 +10612,8 @@ static int amdgpu_dm_atomic_check(struct drm_device *dev, #if defined(CONFIG_DRM_AMD_DC_DCN) struct dsc_mst_fairness_vars vars[MAX_PIPES]; #endif + struct drm_dp_mst_topology_state *mst_state; + struct drm_dp_mst_topology_mgr *mgr;trace_amdgpu_dm_atomic_check_begin(state); @@ -10819,6 +10821,32 @@ static int amdgpu_dm_atomic_check(struct drm_device *dev,lock_and_validation_needed = true; }+#if defined(CONFIG_DRM_AMD_DC_DCN)+ for_each_new_mst_mgr_in_state(state, mgr, mst_state, i) { + struct amdgpu_dm_connector *aconnector; + struct drm_connector *connector; + struct drm_connector_list_iter iter; + u8 link_coding_cap; + + if (!mgr->mst_state ) + continue; + + drm_connector_list_iter_begin(dev, &iter); + drm_for_each_connector_iter(connector, &iter) { + int id = connector->index; + + if (id == mst_state->mgr->conn_base_id) { + aconnector = to_amdgpu_dm_connector(connector); + link_coding_cap = dc_link_dp_mst_decide_link_encoding_format(aconnector->dc_link); + drm_dp_mst_update_coding_cap(mst_state, link_coding_cap); + + break; + } + } + drm_connector_list_iter_end(&iter); + + } +#endifI wonder if we could split this to separate drm dp helper and amd driver patches?
I agree, 8b/10 are the default, but in case where we switch from 128b/132 -> 8b/10b we should be updating them here aswell./** * Streams and planes are reset when there are changes that affect * bandwidth. Anything that affects bandwidth needs to go through diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c index ad0795afc21c..fb5c47c4cb2e 100644 --- a/drivers/gpu/drm/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/drm_dp_mst_topology.c @@ -3368,7 +3368,7 @@ int drm_dp_update_payload_part1(struct drm_dp_mst_topology_mgr *mgr) struct drm_dp_payload req_payload; struct drm_dp_mst_port *port; int i, j; - int cur_slots = 1; + int cur_slots = mgr->start_slot; bool skip;mutex_lock(&mgr->payload_lock);@@ -4321,7 +4321,7 @@ int drm_dp_find_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr, num_slots = DIV_ROUND_UP(pbn, mgr->pbn_div);/* max. time slots - one slot for MTP header */- if (num_slots > 63) + if (num_slots > mgr->total_avail_slots) return -ENOSPC; return num_slots; } @@ -4333,7 +4333,7 @@ static int drm_dp_init_vcpi(struct drm_dp_mst_topology_mgr *mgr, int ret;/* max. time slots - one slot for MTP header */- if (slots > 63) + if (slots > mgr->total_avail_slots) return -ENOSPC;vcpi->pbn = pbn;@@ -4507,6 +4507,18 @@ int drm_dp_atomic_release_vcpi_slots(struct drm_atomic_state *state, } EXPORT_SYMBOL(drm_dp_atomic_release_vcpi_slots);+void drm_dp_mst_update_coding_cap(struct drm_dp_mst_topology_state *mst_state, uint8_t link_coding_cap)+{ + if (link_coding_cap == DP_CAP_ANSI_128B132B) { + mst_state->total_avail_slots = 64; + mst_state->start_slot = 0; + }The values never change AFAICT, should we store the channel encoding instead, and use that information to initialize the values? (Alternatively, why aren't the 8b/10b values initialized here if 128b/132b are?)
previously we were setting it directly in the mgr, and this was suggested by lyude. I am not sure what the alternative is.+ + DRM_DEBUG_KMS("%s coding format on mgr 0x%p\n", + (link_coding_cap == DP_CAP_ANSI_128B132B) ? "128b/132b":"8b/10b", mst_state->mgr); +} +EXPORT_SYMBOL(drm_dp_mst_update_coding_cap); + /** * drm_dp_mst_allocate_vcpi() - Allocate a virtual channel * @mgr: manager for this port @@ -4538,8 +4550,8 @@ bool drm_dp_mst_allocate_vcpi(struct drm_dp_mst_topology_mgr *mgr,ret = drm_dp_init_vcpi(mgr, &port->vcpi, pbn, slots);if (ret) { - drm_dbg_kms(mgr->dev, "failed to init vcpi slots=%d max=63 ret=%d\n", - DIV_ROUND_UP(pbn, mgr->pbn_div), ret); + drm_dbg_kms(mgr->dev, "failed to init vcpi slots=%d max=%d ret=%d\n", + DIV_ROUND_UP(pbn, mgr->pbn_div), mgr->total_avail_slots, ret); drm_dp_mst_topology_put_port(port); goto out; } @@ -5226,7 +5238,7 @@ drm_dp_mst_atomic_check_vcpi_alloc_limit(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, payload_count = 0; + int avail_slots = mgr->total_avail_slots, payload_count = 0;list_for_each_entry(vcpi, &mst_state->vcpis, next) {/* Releasing VCPI is always OK-even if the port is gone */ @@ -5255,7 +5267,7 @@ drm_dp_mst_atomic_check_vcpi_alloc_limit(struct drm_dp_mst_topology_mgr *mgr, } } drm_dbg_atomic(mgr->dev, "[MST MGR:%p] mst state %p VCPI avail=%d used=%d\n", - mgr, mst_state, avail_slots, 63 - avail_slots); + mgr, mst_state, avail_slots, mgr->total_avail_slots - avail_slots);return 0;} @@ -5421,6 +5433,10 @@ int drm_dp_mst_atomic_check(struct drm_atomic_state *state) break;mutex_lock(&mgr->lock);+ + mgr->start_slot = mst_state->start_slot; + mgr->total_avail_slots = mst_state->total_avail_slots; +It feels wrong to me to be copying stuff from mst_state to mgr in general, and in atomic check hook in particular.
ret = drm_dp_mst_atomic_check_mstb_bw_limit(mgr->mst_primary, mst_state); mutex_unlock(&mgr->lock); @@ -5527,11 +5543,16 @@ int drm_dp_mst_topology_mgr_init(struct drm_dp_mst_topology_mgr *mgr, if (!mgr->proposed_vcpis) return -ENOMEM; set_bit(0, &mgr->payload_mask); + mgr->total_avail_slots = 63; + mgr->start_slot = 1;mst_state = kzalloc(sizeof(*mst_state), GFP_KERNEL);if (mst_state == NULL) return -ENOMEM;+ mst_state->total_avail_slots = 63;+ mst_state->start_slot = 1; +The magic values for 8b/10b are now duplicated to two places, with the 128b/132b values in a separate place.
8b/10b is the default (to make sure we don't break any existing driver that doesn't use 128b/132b). Are you against setting it as the default here? or do you mean we should use #define for this? the magic numbers are currently being used directly right now (inside drm_dp_find_vcpi_slots, drm_dp_init_vcpi).
Bhawan
BR, Jani.mst_state->mgr = mgr; INIT_LIST_HEAD(&mst_state->vcpis);diff --git a/include/drm/drm_dp_mst_helper.h b/include/drm/drm_dp_mst_helper.hindex ddb9231d0309..f8152dfb34ed 100644 --- a/include/drm/drm_dp_mst_helper.h +++ b/include/drm/drm_dp_mst_helper.h @@ -554,6 +554,8 @@ struct drm_dp_mst_topology_state { struct drm_private_state base; struct list_head vcpis; struct drm_dp_mst_topology_mgr *mgr; + u8 total_avail_slots; + u8 start_slot; };#define to_dp_mst_topology_mgr(x) container_of(x, struct drm_dp_mst_topology_mgr, base)@@ -661,6 +663,16 @@ struct drm_dp_mst_topology_mgr { */ int pbn_div;+ /**+ * @total_avail_slots: 63 for 8b/10b, 64 for 128/132b + */ + u8 total_avail_slots; + + /** + * @start_slot: 1 for 8b/10b, 0 for 128/132b + */ + u8 start_slot; + /** * @funcs: Atomic helper callbacks */ @@ -806,6 +818,7 @@ int drm_dp_mst_get_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr, struct drm_dpvoid drm_dp_mst_reset_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port); +void drm_dp_mst_update_coding_cap(struct drm_dp_mst_topology_state *mst_state, uint8_t link_coding_cap); void drm_dp_mst_deallocate_vcpi(struct drm_dp_mst_topology_mgr *mgr,struct drm_dp_mst_port *port);
