From 191dc43935d1ece82bc6c9653463b3b1cd8198fb Mon Sep 17 00:00:00 2001 From: Imre Deak Date: Thu, 16 Nov 2023 15:18:31 +0200 Subject: [PATCH] drm/dp_mst: Store the MST PBN divider value in fixed point format MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit On UHBR links the PBN divider is a fractional number, accordingly store it in fixed point format. For now drm_dp_get_vc_payload_bw() always returns a whole number and all callers will use only the integer part of it which should preserve the current behavior. The next patch will fix drm_dp_get_vc_payload_bw() for UHBR rates returning a fractional number for those (also accounting for the channel coding efficiency correctly). Cc: Lyude Paul Cc: Harry Wentland Cc: Alex Deucher Cc: Wayne Lin Cc: amd-gfx@lists.freedesktop.org Cc: dri-devel@lists.freedesktop.org Reviewed-by: Ville Syrjälä Acked-by: Daniel Vetter Acked-by: Maarten Lankhorst [Rebased changes in dm_helpers_construct_old_payload() on drm-intel-next] Signed-off-by: Imre Deak Link: https://patchwork.freedesktop.org/patch/msgid/20231116131841.1588781-2-imre.deak@intel.com --- .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 5 +++-- .../amd/display/amdgpu_dm/amdgpu_dm_helpers.c | 4 +++- .../display/amdgpu_dm/amdgpu_dm_mst_types.c | 5 +++-- drivers/gpu/drm/display/drm_dp_mst_topology.c | 22 +++++++++++++------ drivers/gpu/drm/i915/display/intel_dp_mst.c | 3 ++- drivers/gpu/drm/nouveau/dispnv50/disp.c | 6 +++-- include/drm/display/drm_dp_mst_helper.h | 7 +++--- 7 files changed, 34 insertions(+), 18 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 df3c42bb9274..2253e8fd2d18 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c @@ -85,6 +85,7 @@ #include #include #include +#include #include #include #include @@ -6863,8 +6864,8 @@ static int dm_encoder_helper_atomic_check(struct drm_encoder *encoder, if (IS_ERR(mst_state)) return PTR_ERR(mst_state); - if (!mst_state->pbn_div) - mst_state->pbn_div = dm_mst_get_pbn_divider(aconnector->mst_root->dc_link); + if (!mst_state->pbn_div.full) + mst_state->pbn_div.full = dfixed_const(dm_mst_get_pbn_divider(aconnector->mst_root->dc_link)); if (!state->duplicated) { int max_bpc = conn_state->max_requested_bpc; diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c index baf7e5254fb3..53e323b71d26 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c @@ -31,6 +31,7 @@ #include #include #include +#include #include "dm_services.h" #include "amdgpu.h" @@ -205,13 +206,14 @@ void dm_helpers_dp_update_branch_info( static void dm_helpers_construct_old_payload( struct dc_link *link, - int pbn_per_slot, + fixed20_12 pbn_per_slot_fp, struct drm_dp_mst_atomic_payload *new_payload, struct drm_dp_mst_atomic_payload *old_payload) { struct link_mst_stream_allocation_table current_link_table = link->mst_stream_alloc_table; struct link_mst_stream_allocation *dc_alloc; + int pbn_per_slot = dfixed_trunc(pbn_per_slot_fp); int i; *old_payload = *new_payload; diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c index 2afd1bc74978..d80f19e442bf 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c @@ -27,6 +27,7 @@ #include #include #include +#include #include "dm_services.h" #include "amdgpu.h" #include "amdgpu_dm.h" @@ -935,10 +936,10 @@ static int increase_dsc_bpp(struct drm_atomic_state *state, link_timeslots_used = 0; for (i = 0; i < count; i++) - link_timeslots_used += DIV_ROUND_UP(vars[i + k].pbn, mst_state->pbn_div); + link_timeslots_used += DIV_ROUND_UP(vars[i + k].pbn, dfixed_trunc(mst_state->pbn_div)); fair_pbn_alloc = - (63 - link_timeslots_used) / remaining_to_increase * mst_state->pbn_div; + (63 - link_timeslots_used) / remaining_to_increase * dfixed_trunc(mst_state->pbn_div); if (initial_slack[next_index] > fair_pbn_alloc) { vars[next_index].pbn += fair_pbn_alloc; diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c b/drivers/gpu/drm/display/drm_dp_mst_topology.c index 0854fe428f17..7efbd8ef664f 100644 --- a/drivers/gpu/drm/display/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c @@ -43,6 +43,7 @@ #include #include #include +#include #include #include @@ -3578,16 +3579,22 @@ static int drm_dp_send_up_ack_reply(struct drm_dp_mst_topology_mgr *mgr, * value is in units of PBNs/(timeslots/1 MTP). This value can be used to * convert the number of PBNs required for a given stream to the number of * timeslots this stream requires in each MTP. + * + * Returns the BW / timeslot value in 20.12 fixed point format. */ -int drm_dp_get_vc_payload_bw(const struct drm_dp_mst_topology_mgr *mgr, - int link_rate, int link_lane_count) +fixed20_12 drm_dp_get_vc_payload_bw(const struct drm_dp_mst_topology_mgr *mgr, + int link_rate, int link_lane_count) { + fixed20_12 ret; + if (link_rate == 0 || link_lane_count == 0) drm_dbg_kms(mgr->dev, "invalid link rate/lane count: (%d / %d)\n", link_rate, link_lane_count); /* See DP v2.0 2.6.4.2, VCPayload_Bandwidth_for_OneTimeSlotPer_MTP_Allocation */ - return link_rate * link_lane_count / 54000; + ret.full = dfixed_const(link_rate * link_lane_count / 54000); + + return ret; } EXPORT_SYMBOL(drm_dp_get_vc_payload_bw); @@ -4335,7 +4342,7 @@ int drm_dp_atomic_find_time_slots(struct drm_atomic_state *state, } } - req_slots = DIV_ROUND_UP(pbn, topology_state->pbn_div); + req_slots = DIV_ROUND_UP(pbn, dfixed_trunc(topology_state->pbn_div)); drm_dbg_atomic(mgr->dev, "[CONNECTOR:%d:%s] [MST PORT:%p] TU %d -> %d\n", port->connector->base.id, port->connector->name, @@ -4872,7 +4879,8 @@ void drm_dp_mst_dump_topology(struct seq_file *m, state = to_drm_dp_mst_topology_state(mgr->base.state); seq_printf(m, "\n*** Atomic state info ***\n"); seq_printf(m, "payload_mask: %x, max_payloads: %d, start_slot: %u, pbn_div: %d\n", - state->payload_mask, mgr->max_payloads, state->start_slot, state->pbn_div); + state->payload_mask, mgr->max_payloads, state->start_slot, + dfixed_trunc(state->pbn_div)); seq_printf(m, "\n| idx | port | vcpi | slots | pbn | dsc | status | sink name |\n"); for (i = 0; i < mgr->max_payloads; i++) { @@ -5330,10 +5338,10 @@ drm_dp_mst_atomic_check_payload_alloc_limits(struct drm_dp_mst_topology_mgr *mgr } if (!payload_count) - mst_state->pbn_div = 0; + mst_state->pbn_div.full = dfixed_const(0); drm_dbg_atomic(mgr->dev, "[MST MGR:%p] mst state %p TU pbn_div=%d avail=%d used=%d\n", - mgr, mst_state, mst_state->pbn_div, avail_slots, + mgr, mst_state, dfixed_trunc(mst_state->pbn_div), avail_slots, mst_state->total_avail_slots - avail_slots); return 0; diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c index 0cb9405f59ea..e5d6b811c22e 100644 --- a/drivers/gpu/drm/i915/display/intel_dp_mst.c +++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c @@ -26,6 +26,7 @@ #include #include #include +#include #include #include "i915_drv.h" @@ -202,7 +203,7 @@ static int intel_dp_mst_find_vcpi_slots_for_bpp(struct intel_encoder *encoder, */ drm_WARN_ON(&i915->drm, remote_m_n.tu < crtc_state->dp_m_n.tu); crtc_state->dp_m_n.tu = remote_m_n.tu; - crtc_state->pbn = remote_m_n.tu * mst_state->pbn_div; + crtc_state->pbn = remote_m_n.tu * dfixed_trunc(mst_state->pbn_div); slots = drm_dp_atomic_find_time_slots(state, &intel_dp->mst_mgr, connector->port, diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.c b/drivers/gpu/drm/nouveau/dispnv50/disp.c index 3d390f5029f6..95fb097e5453 100644 --- a/drivers/gpu/drm/nouveau/dispnv50/disp.c +++ b/drivers/gpu/drm/nouveau/dispnv50/disp.c @@ -39,6 +39,7 @@ #include #include #include +#include #include #include @@ -945,7 +946,8 @@ nv50_msto_prepare(struct drm_atomic_state *state, if (ret == 0) { nvif_outp_dp_mst_vcpi(&mstm->outp->outp, msto->head->base.index, payload->vc_start_slot, payload->time_slots, - payload->pbn, payload->time_slots * mst_state->pbn_div); + payload->pbn, + payload->time_slots * dfixed_trunc(mst_state->pbn_div)); } else { nvif_outp_dp_mst_vcpi(&mstm->outp->outp, msto->head->base.index, 0, 0, 0, 0); } @@ -989,7 +991,7 @@ nv50_msto_atomic_check(struct drm_encoder *encoder, if (IS_ERR(mst_state)) return PTR_ERR(mst_state); - if (!mst_state->pbn_div) { + if (!mst_state->pbn_div.full) { struct nouveau_encoder *outp = mstc->mstm->outp; mst_state->pbn_div = drm_dp_get_vc_payload_bw(&mstm->mgr, diff --git a/include/drm/display/drm_dp_mst_helper.h b/include/drm/display/drm_dp_mst_helper.h index a4aad6df71f1..9b19d8bd520a 100644 --- a/include/drm/display/drm_dp_mst_helper.h +++ b/include/drm/display/drm_dp_mst_helper.h @@ -25,6 +25,7 @@ #include #include #include +#include #if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS) #include @@ -617,7 +618,7 @@ struct drm_dp_mst_topology_state { * @pbn_div: The current PBN divisor for this topology. The driver is expected to fill this * out itself. */ - int pbn_div; + fixed20_12 pbn_div; }; #define to_dp_mst_topology_mgr(x) container_of(x, struct drm_dp_mst_topology_mgr, base) @@ -839,8 +840,8 @@ struct edid *drm_dp_mst_get_edid(struct drm_connector *connector, struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port); -int drm_dp_get_vc_payload_bw(const struct drm_dp_mst_topology_mgr *mgr, - int link_rate, int link_lane_count); +fixed20_12 drm_dp_get_vc_payload_bw(const struct drm_dp_mst_topology_mgr *mgr, + int link_rate, int link_lane_count); int drm_dp_calc_pbn_mode(int clock, int bpp); -- 2.25.1