drm/amd/display: Optimize link power-down when link powered externally

[Why]
When an eDP panel is powered externally by a different GPU, we don't need
to wait for hardware sequencing delays when powering down a link, as the
display is not dependent on the GPU being powered down.

[How]
This commit adds a variable 'link_powered_externally' to indicate when a
link is being powered by another GPU.

Tested-by: Daniel Wheeler <Daniel.Wheeler@amd.com>
Reviewed-by: Felipe Clark <felipe.clark@amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Tony Tascioglu <tony.tascioglu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/bios/bios_parser2.c

@@ -1697,14 +1697,15 @@ static enum bp_result bios_parser_enable_disp_power_gating(
 static enum bp_result bios_parser_enable_lvtma_control(
 	struct dc_bios *dcb,
 	uint8_t uc_pwr_on,
-	uint8_t panel_instance)
+	uint8_t panel_instance,
+	uint8_t bypass_powerdown_wait)
 {
 	struct bios_parser *bp = BP_FROM_DCB(dcb);
 
 	if (!bp->cmd_tbl.enable_lvtma_control)
 		return BP_RESULT_FAILURE;
 
-	return bp->cmd_tbl.enable_lvtma_control(bp, uc_pwr_on, panel_instance);
+	return bp->cmd_tbl.enable_lvtma_control(bp, uc_pwr_on, panel_instance, bypass_powerdown_wait);
 }
 
 static bool bios_parser_is_accelerated_mode(

drivers/gpu/drm/amd/display/dc/bios/command_table2.c

@@ -986,7 +986,8 @@ static unsigned int get_smu_clock_info_v3_1(struct bios_parser *bp, uint8_t id)
 static enum bp_result enable_lvtma_control(
 	struct bios_parser *bp,
 	uint8_t uc_pwr_on,
-	uint8_t panel_instance);
+	uint8_t panel_instance,
+	uint8_t bypass_powerdown_wait);
 
 static void init_enable_lvtma_control(struct bios_parser *bp)
 {
@@ -998,7 +999,8 @@ static void init_enable_lvtma_control(struct bios_parser *bp)
 static void enable_lvtma_control_dmcub(
 	struct dc_dmub_srv *dmcub,
 	uint8_t uc_pwr_on,
-	uint8_t panel_instance)
+	uint8_t panel_instance,
+	uint8_t bypass_powerdown_wait)
 {
 
 	union dmub_rb_cmd cmd;
@@ -1012,6 +1014,8 @@ static void enable_lvtma_control_dmcub(
 			uc_pwr_on;
 	cmd.lvtma_control.data.panel_inst =
 			panel_instance;
+	cmd.lvtma_control.data.bypass_powerdown_wait =
+			bypass_powerdown_wait;
 	dc_dmub_srv_cmd_queue(dmcub, &cmd);
 	dc_dmub_srv_cmd_execute(dmcub);
 	dc_dmub_srv_wait_idle(dmcub);
@@ -1021,7 +1025,8 @@ static void enable_lvtma_control_dmcub(
 static enum bp_result enable_lvtma_control(
 	struct bios_parser *bp,
 	uint8_t uc_pwr_on,
-	uint8_t panel_instance)
+	uint8_t panel_instance,
+	uint8_t bypass_powerdown_wait)
 {
 	enum bp_result result = BP_RESULT_FAILURE;
 
@@ -1029,7 +1034,8 @@ static enum bp_result enable_lvtma_control(
 	    bp->base.ctx->dc->debug.dmub_command_table) {
 		enable_lvtma_control_dmcub(bp->base.ctx->dmub_srv,
 				uc_pwr_on,
-				panel_instance);
+				panel_instance,
+				bypass_powerdown_wait);
 		return BP_RESULT_OK;
 	}
 	return result;

drivers/gpu/drm/amd/display/dc/bios/command_table2.h

@@ -96,7 +96,8 @@ struct cmd_tbl {
 			struct bios_parser *bp, uint8_t id);
 	enum bp_result (*enable_lvtma_control)(struct bios_parser *bp,
 			uint8_t uc_pwr_on,
-			uint8_t panel_instance);
+			uint8_t panel_instance,
+			uint8_t bypass_powerdown_wait);
 };
 
 void dal_firmware_parser_init_cmd_tbl(struct bios_parser *bp);

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

@@ -140,7 +140,8 @@ struct dc_vbios_funcs {
 	enum bp_result (*enable_lvtma_control)(
 		struct dc_bios *bios,
 		uint8_t uc_pwr_on,
-		uint8_t panel_instance);
+		uint8_t panel_instance,
+		uint8_t bypass_powerdown_wait);
 
 	enum bp_result (*get_soc_bb_info)(
 		struct dc_bios *dcb,

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

@@ -294,6 +294,8 @@ struct dc_link {
 
 	struct gpio *hpd_gpio;
 	enum dc_link_fec_state fec_state;
+	bool link_powered_externally;	// Used to bypass hardware sequencing delays when panel is powered down forcibly
+
 	struct dc_panel_config panel_config;
 	struct phy_state phy_state;
 };

drivers/gpu/drm/amd/display/dc/dce110/dce110_hw_sequencer.c

@@ -875,14 +875,16 @@ void dce110_edp_power_control(
 
 		if (ctx->dc->ctx->dmub_srv &&
 				ctx->dc->debug.dmub_command_table) {
-			if (cntl.action == TRANSMITTER_CONTROL_POWER_ON)
+
+			if (cntl.action == TRANSMITTER_CONTROL_POWER_ON) {
 				bp_result = ctx->dc_bios->funcs->enable_lvtma_control(ctx->dc_bios,
 						LVTMA_CONTROL_POWER_ON,
-						panel_instance);
+						panel_instance, link->link_powered_externally);
-			else
+			} else {
 				bp_result = ctx->dc_bios->funcs->enable_lvtma_control(ctx->dc_bios,
 						LVTMA_CONTROL_POWER_OFF,
-						panel_instance);
+						panel_instance, link->link_powered_externally);
+			}
 		}
 
 		bp_result = link_transmitter_control(ctx->dc_bios, &cntl);
@@ -1025,11 +1027,11 @@ void dce110_edp_backlight_control(
 		if (cntl.action == TRANSMITTER_CONTROL_BACKLIGHT_ON)
 			ctx->dc_bios->funcs->enable_lvtma_control(ctx->dc_bios,
 					LVTMA_CONTROL_LCD_BLON,
-					panel_instance);
+					panel_instance, 0);
 		else
 			ctx->dc_bios->funcs->enable_lvtma_control(ctx->dc_bios,
 					LVTMA_CONTROL_LCD_BLOFF,
-					panel_instance);
+					panel_instance, 0);
 	}
 
 	link_transmitter_control(ctx->dc_bios, &cntl);

drivers/gpu/drm/amd/display/dmub/inc/dmub_cmd.h

@@ -3111,7 +3111,8 @@ struct dmub_rb_cmd_panel_cntl {
  */
 struct dmub_cmd_lvtma_control_data {
 	uint8_t uc_pwr_action; /**< LVTMA_ACTION */
-	uint8_t reserved_0[3]; /**< For future use */
+	uint8_t bypass_powerdown_wait;
+	uint8_t reserved_0[2];
 	uint8_t panel_inst; /**< LVTMA control instance */
 	uint8_t reserved_1[3]; /**< For future use */
 };