drm/amd/display: DAL to program DISPCLK WDIVIDER if PMFW doesn't

[Why & How]
- If for any reason PMFW fails to set the expected (or valid)
  DISPCLK WDIVIDER, then DAL will program DENTIST DISPCLK
  WDIVIDER to correct for this issue
Reviewed-by: Samson Tam <Samson.Tam@amd.com>
Acked-by: Qingqing Zhuo <qingqing.zhuo@amd.com>
Signed-off-by: Alvin Lee <Alvin.Lee2@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/clk_mgr/dcn32/dcn32_clk_mgr.c

@@ -257,25 +257,24 @@ static void dcn32_update_dppclk_dispclk_freq(struct clk_mgr_internal *clk_mgr, s
 
 static void dcn32_update_clocks_update_dentist(
 		struct clk_mgr_internal *clk_mgr,
-		struct dc_state *context,
-		uint32_t old_dispclk_khz)
+		struct dc_state *context)
 {
 	uint32_t new_disp_divider = 0;
-	uint32_t old_disp_divider = 0;
 	uint32_t new_dispclk_wdivider = 0;
 	uint32_t old_dispclk_wdivider = 0;
 	uint32_t i;
+	uint32_t dentist_dispclk_wdivider_readback = 0;
+	struct dc *dc = clk_mgr->base.ctx->dc;
 
-	if (old_dispclk_khz == 0 || clk_mgr->base.clks.dispclk_khz == 0)
+	if (clk_mgr->base.clks.dispclk_khz == 0)
 		return;
 
 	new_disp_divider = DENTIST_DIVIDER_RANGE_SCALE_FACTOR
 			* clk_mgr->base.dentist_vco_freq_khz / clk_mgr->base.clks.dispclk_khz;
-	old_disp_divider = DENTIST_DIVIDER_RANGE_SCALE_FACTOR
-			* clk_mgr->base.dentist_vco_freq_khz / old_dispclk_khz;
 
 	new_dispclk_wdivider = dentist_get_did_from_divider(new_disp_divider);
-	old_dispclk_wdivider = dentist_get_did_from_divider(old_disp_divider);
+	REG_GET(DENTIST_DISPCLK_CNTL,
+			DENTIST_DISPCLK_WDIVIDER, &old_dispclk_wdivider);
 
 	/* When changing divider to or from 127, some extra programming is required to prevent corruption */
 	if (old_dispclk_wdivider == 127 && new_dispclk_wdivider != 127) {
@@ -314,6 +313,17 @@ static void dcn32_update_clocks_update_dentist(
 		if (clk_mgr->smu_present)
 			dcn32_smu_set_hard_min_by_freq(clk_mgr, PPCLK_DISPCLK, khz_to_mhz_ceil(temp_dispclk_khz));
 
+		if (dc->debug.override_dispclk_programming) {
+			REG_GET(DENTIST_DISPCLK_CNTL,
+					DENTIST_DISPCLK_WDIVIDER, &dentist_dispclk_wdivider_readback);
+
+			if (dentist_dispclk_wdivider_readback != 126) {
+				REG_UPDATE(DENTIST_DISPCLK_CNTL,
+						DENTIST_DISPCLK_WDIVIDER, 126);
+				REG_WAIT(DENTIST_DISPCLK_CNTL, DENTIST_DISPCLK_CHG_DONE, 1, 50, 2000);
+			}
+		}
+
 		for (i = 0; i < clk_mgr->base.ctx->dc->res_pool->pipe_count; i++) {
 			struct pipe_ctx *pipe_ctx = &context->res_ctx.pipe_ctx[i];
 			struct dccg *dccg = clk_mgr->base.ctx->dc->res_pool->dccg;
@@ -341,6 +351,18 @@ static void dcn32_update_clocks_update_dentist(
 	/* do requested DISPCLK updates*/
 	if (clk_mgr->smu_present)
 		dcn32_smu_set_hard_min_by_freq(clk_mgr, PPCLK_DISPCLK, khz_to_mhz_ceil(clk_mgr->base.clks.dispclk_khz));
+
+	if (dc->debug.override_dispclk_programming) {
+		REG_GET(DENTIST_DISPCLK_CNTL,
+				DENTIST_DISPCLK_WDIVIDER, &dentist_dispclk_wdivider_readback);
+
+		if (dentist_dispclk_wdivider_readback > new_dispclk_wdivider) {
+			REG_UPDATE(DENTIST_DISPCLK_CNTL,
+					DENTIST_DISPCLK_WDIVIDER, new_dispclk_wdivider);
+			REG_WAIT(DENTIST_DISPCLK_CNTL, DENTIST_DISPCLK_CHG_DONE, 1, 50, 2000);
+		}
+	}
+
 }
 
 static void dcn32_update_clocks(struct clk_mgr *clk_mgr_base,
@@ -361,7 +383,6 @@ static void dcn32_update_clocks(struct clk_mgr *clk_mgr_base,
 	bool p_state_change_support;
 	bool fclk_p_state_change_support;
 	int total_plane_count;
-	int old_dispclk_khz = clk_mgr_base->clks.dispclk_khz;
 
 	if (dc->work_arounds.skip_clock_update)
 		return;
@@ -504,13 +525,13 @@ static void dcn32_update_clocks(struct clk_mgr *clk_mgr_base,
 		if (dpp_clock_lowered) {
 			/* if clock is being lowered, increase DTO before lowering refclk */
 			dcn20_update_clocks_update_dpp_dto(clk_mgr, context, safe_to_lower);
-			dcn32_update_clocks_update_dentist(clk_mgr, context, old_dispclk_khz);
+			dcn32_update_clocks_update_dentist(clk_mgr, context);
 			if (clk_mgr->smu_present)
 				dcn32_smu_set_hard_min_by_freq(clk_mgr, PPCLK_DPPCLK, khz_to_mhz_ceil(clk_mgr_base->clks.dppclk_khz));
 		} else {
 			/* if clock is being raised, increase refclk before lowering DTO */
 			if (update_dppclk || update_dispclk)
-				dcn32_update_clocks_update_dentist(clk_mgr, context, old_dispclk_khz);
+				dcn32_update_clocks_update_dentist(clk_mgr, context);
 			/* There is a check inside dcn20_update_clocks_update_dpp_dto which ensures
 			 * that we do not lower dto when it is not safe to lower. We do not need to
 			 * compare the current and new dppclk before calling this function.

drivers/gpu/drm/amd/display/dc/dc.h

@@ -874,6 +874,7 @@ struct dc_debug_options {
 	bool disable_unbounded_requesting;
 	bool dig_fifo_off_in_blank;
 	bool temp_mst_deallocation_sequence;
+	bool override_dispclk_programming;
 };
 
 struct gpu_info_soc_bounding_box_v1_0;

drivers/gpu/drm/amd/display/dc/dcn32/dcn32_resource.c

@@ -726,6 +726,7 @@ static const struct dc_debug_options debug_defaults_drv = {
 	.alloc_extra_way_for_cursor = true,
 	.min_prefetch_in_strobe_ns = 60000, // 60us
 	.disable_unbounded_requesting = false,
+	.override_dispclk_programming = true,
 };
 
 static const struct dc_debug_options debug_defaults_diags = {

drivers/gpu/drm/amd/display/dc/dcn321/dcn321_resource.c

@@ -724,6 +724,7 @@ static const struct dc_debug_options debug_defaults_drv = {
 	.alloc_extra_way_for_cursor = true,
 	.min_prefetch_in_strobe_ns = 60000, // 60us
 	.disable_unbounded_requesting = false,
+	.override_dispclk_programming = true,
 };
 
 static const struct dc_debug_options debug_defaults_diags = {