drm/amd/display: Override min required DCFCLK in dml1_validate

[WHY]:
Increasing min DCFCLK addresses underflow issues that occur when phantom
pipe is turned on for some Sub-Viewport configs

[HOW]:
dcn32_override_min_req_dcfclk is added to override DCFCLK value in
dml1_validate when subviewport is being used.

Cc: Mario Limonciello <mario.limonciello@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Reviewed-by: Alvin Lee <alvin.lee2@amd.com>
Acked-by: Alex Hung <alex.hung@amd.com>
Signed-off-by: Sohaib Nadeem <sohaib.nadeem@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/dcn32/dcn32_resource_helpers.c

@@ -782,3 +782,9 @@ void dcn32_update_dml_pipes_odm_policy_based_on_context(struct dc *dc, struct dc
 		pipe_cnt++;
 	}
 }
+
+void dcn32_override_min_req_dcfclk(struct dc *dc, struct dc_state *context)
+{
+	if (dcn32_subvp_in_use(dc, context) && context->bw_ctx.bw.dcn.clk.dcfclk_khz <= MIN_SUBVP_DCFCLK_KHZ)
+		context->bw_ctx.bw.dcn.clk.dcfclk_khz = MIN_SUBVP_DCFCLK_KHZ;
+}

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

@@ -1771,6 +1771,7 @@ static bool dml1_validate(struct dc *dc, struct dc_state *context, bool fast_val
 	dc->res_pool->funcs->calculate_wm_and_dlg(dc, context, pipes, pipe_cnt, vlevel);
 
 	dcn32_override_min_req_memclk(dc, context);
+	dcn32_override_min_req_dcfclk(dc, context);
 
 	BW_VAL_TRACE_END_WATERMARKS();
 

drivers/gpu/drm/amd/display/dc/resource/dcn32/dcn32_resource.h

@@ -42,6 +42,7 @@
 #define SUBVP_ACTIVE_MARGIN_LIST_LEN 2
 #define DCN3_2_MAX_SUBVP_PIXEL_RATE_MHZ 1800
 #define DCN3_2_VMIN_DISPCLK_HZ 717000000
+#define MIN_SUBVP_DCFCLK_KHZ 400000
 
 #define TO_DCN32_RES_POOL(pool)\
 	container_of(pool, struct dcn32_resource_pool, base)
@@ -181,6 +182,8 @@ bool dcn32_subvp_vblank_admissable(struct dc *dc, struct dc_state *context, int
 
 void dcn32_update_dml_pipes_odm_policy_based_on_context(struct dc *dc, struct dc_state *context, display_e2e_pipe_params_st *pipes);
 
+void dcn32_override_min_req_dcfclk(struct dc *dc, struct dc_state *context);
+
 /* definitions for run time init of reg offsets */
 
 /* CLK SRC */