drm/amd/display: Make clk mgr the only dto update point

[Why]

* Clk Mgr DTO update point did not cover all needed updates, as it included a
  check for plane_state which does not exist yet when the updater is called on
  driver startup
* This resulted in another update path in the pipe programming sequence, based
  on a dppclk update flag
* However, this alternate path allowed for stray DTO updates, some of which would
  occur in the wrong order during dppclk lowering and cause underflow

[How]

* Remove plane_state check and use of plane_res.dpp->inst, getting rid
  of sequence dependencies (this results in extra dto programming for unused
  pipes but that doesn't cause issues and is a small cost)
* Allow DTOs to be updated even if global clock is equal, to account for
  edge case exposed by diags tests
* Remove update_dpp_dto call in pipe programming sequence (leave update to
  dppclk_control there, as that update is necessary and shouldn't occur in clk
  mgr)
* Remove call to optimize_bandwidth when committing state, as it is not needed
  and resulted in sporadic underflows even with other fixes in place

Signed-off-by: Noah Abradjian <noah.abradjian@amd.com>
Reviewed-by: Jun Lei <Jun.Lei@amd.com>
Acked-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

4 files changed, 12 insertions, 17 deletions

diff --git a/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn20/dcn20_clk_mgr.c b/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn20/dcn20_clk_mgr.c
index 607d8afc56ec..25d7b7c6681c 100644
--- a/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn20/dcn20_clk_mgr.c
+++ b/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn20/dcn20_clk_mgr.c
@@ -108,11 +108,12 @@ void dcn20_update_clocks_update_dpp_dto(struct clk_mgr_internal *clk_mgr,
 	for (i = 0; i < clk_mgr->base.ctx->dc->res_pool->pipe_count; i++) {
 		int dpp_inst, dppclk_khz;
 
-		if (!context->res_ctx.pipe_ctx[i].plane_state)
-			continue;
-
-		dpp_inst = context->res_ctx.pipe_ctx[i].plane_res.dpp->inst;
+		/* Loop index will match dpp->inst if resource exists,
+		 * and we want to avoid dependency on dpp object
+		 */
+		dpp_inst = i;
 		dppclk_khz = context->res_ctx.pipe_ctx[i].plane_res.bw.dppclk_khz;
+
 		clk_mgr->dccg->funcs->update_dpp_dto(
 				clk_mgr->dccg, dpp_inst, dppclk_khz);
 	}
@@ -235,6 +236,7 @@ void dcn2_update_clocks(struct clk_mgr *clk_mgr_base,
 
 		update_dispclk = true;
 	}
+
 	if (dc->config.forced_clocks == false || (force_reset && safe_to_lower)) {
 		if (dpp_clock_lowered) {
 			// if clock is being lowered, increase DTO before lowering refclk
@@ -244,10 +246,12 @@ void dcn2_update_clocks(struct clk_mgr *clk_mgr_base,
 			// if clock is being raised, increase refclk before lowering DTO
 			if (update_dppclk || update_dispclk)
 				dcn20_update_clocks_update_dentist(clk_mgr);
-			if (update_dppclk)
+			// always update dtos unless clock is lowered and not safe to lower
+			if (new_clocks->dppclk_khz >= dc->current_state->bw_ctx.bw.dcn.clk.dppclk_khz)
 				dcn20_update_clocks_update_dpp_dto(clk_mgr, context);
 		}
 	}
+
 	if (update_dispclk &&
 			dmcu && dmcu->funcs->is_dmcu_initialized(dmcu)) {
 		/*update dmcu for wait_loop count*/
diff --git a/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn21/rn_clk_mgr.c b/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn21/rn_clk_mgr.c
index f64d221ad6f1..790a2d211bd6 100644
--- a/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn21/rn_clk_mgr.c
+++ b/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn21/rn_clk_mgr.c
@@ -171,7 +171,8 @@ void rn_update_clocks(struct clk_mgr *clk_mgr_base,
 		// if clock is being raised, increase refclk before lowering DTO
 		if (update_dppclk || update_dispclk)
 			rn_vbios_smu_set_dppclk(clk_mgr, clk_mgr_base->clks.dppclk_khz);
-		if (update_dppclk)
+		// always update dtos unless clock is lowered and not safe to lower
+		if (new_clocks->dppclk_khz >= dc->current_state->bw_ctx.bw.dcn.clk.dppclk_khz)
 			dcn20_update_clocks_update_dpp_dto(clk_mgr, context);
 	}
 
diff --git a/drivers/gpu/drm/amd/display/dc/core/dc.c b/drivers/gpu/drm/amd/display/dc/core/dc.c
index 5e487bb82861..0a443348df10 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc.c
@@ -1241,10 +1241,6 @@ static enum dc_status dc_commit_state_no_check(struct dc *dc, struct dc_state *c
 
 	dc_enable_stereo(dc, context, dc_streams, context->stream_count);
 
-	if (!dc->optimize_seamless_boot)
-		/* pplib is notified if disp_num changed */
-		dc->hwss.optimize_bandwidth(dc, context);
-
 	for (i = 0; i < context->stream_count; i++)
 		context->streams[i]->mode_changed = false;
 
diff --git a/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hwseq.c b/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hwseq.c
index e237ec39d193..921a36668ced 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hwseq.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hwseq.c
@@ -1202,15 +1202,9 @@ static void dcn20_update_dchubp_dpp(
 	struct dpp *dpp = pipe_ctx->plane_res.dpp;
 	struct dc_plane_state *plane_state = pipe_ctx->plane_state;
 
-	if (pipe_ctx->update_flags.bits.dppclk) {
+	if (pipe_ctx->update_flags.bits.dppclk)
 		dpp->funcs->dpp_dppclk_control(dpp, false, true);
 
-		dc->res_pool->dccg->funcs->update_dpp_dto(
-				dc->res_pool->dccg,
-				dpp->inst,
-				pipe_ctx->plane_res.bw.dppclk_khz);
-	}
-
 	/* TODO: Need input parameter to tell current DCHUB pipe tie to which OTG
 	 * VTG is within DCHUBBUB which is commond block share by each pipe HUBP.
 	 * VTG is 1:1 mapping with OTG. Each pipe HUBP will select which VTG