drm/amd/display: Fix DTBCLK disable requests and SRC_SEL programming

[Description]
- When transitioning FRL / DP2 is not required, we will always request
  DTBCLK = 0Mhz, but PMFW returns the min freq
- This causes us to make DTBCLK requests every time we call optimize
  after transitioning from FRL to non-FRL
- If DTBCLK is not required, request the min instead (then we only need
  to make 1 extra request at boot time)
- Also when programming PIPE_DTO_SRC_SEL, don't programming for DP
  first, just programming once for the required selection (programming
  DP on an HDMI connection then switching back causes corruption)

Reviewed-by: Dillon Varone <[email protected]>
Acked-by: Jasdeep Dhillon <[email protected]>
Signed-off-by: Alvin Lee <[email protected]>
Signed-off-by: Alex Deucher <[email protected]>

Author: Alvin Lee

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

@@ -438,7 +438,7 @@ static void dcn32_update_clocks(struct clk_mgr *clk_mgr_base,
 	}
 
 	if (!new_clocks->dtbclk_en) {
-		new_clocks->ref_dtbclk_khz = 0;
+		new_clocks->ref_dtbclk_khz = clk_mgr_base->bw_params->clk_table.entries[0].dtbclk_mhz * 1000;
 	}
 
 	/* clock limits are received with MHz precision, divide by 1000 to prevent setting clocks at every call */

drivers/gpu/drm/amd/display/dc/dcn32/dcn32_dccg.c

@@ -225,11 +225,7 @@ static void dccg32_set_dtbclk_dto(
 	} else {
 		REG_UPDATE_2(OTG_PIXEL_RATE_CNTL[params->otg_inst],
 				DTBCLK_DTO_ENABLE[params->otg_inst], 0,
-				PIPE_DTO_SRC_SEL[params->otg_inst], 1);
-		if (params->is_hdmi)
-			REG_UPDATE(OTG_PIXEL_RATE_CNTL[params->otg_inst],
-				PIPE_DTO_SRC_SEL[params->otg_inst], 0);
-
+				PIPE_DTO_SRC_SEL[params->otg_inst], params->is_hdmi ? 0 : 1);
 		REG_WRITE(DTBCLK_DTO_MODULO[params->otg_inst], 0);
 		REG_WRITE(DTBCLK_DTO_PHASE[params->otg_inst], 0);
 	}