drm/amd/display: To update backlight restore mechanism

[Why]
Cached backlight is never being updated since panel_cntl specific
registers were moved from abm to panel_cntl.

[How]
Update cached backlight in set_abm_immediate_disable as what we used to
do. Also, update the priority of backlight restore mechanism so that
cached backlight has the highest priority since it is always correct.
Signed-off-by: Camille Cho <Camille.Cho@amd.com>
Reviewed-by: Anthony Koo <Anthony.Koo@amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/dce/dce_panel_cntl.c

@@ -108,7 +108,6 @@ static uint32_t dce_panel_cntl_hw_init(struct panel_cntl *panel_cntl)
 	 */
 	REG_GET(BL_PWM_CNTL, BL_ACTIVE_INT_FRAC_CNT, &value);
 
-	if (value == 0 || value == 1) {
 	if (panel_cntl->stored_backlight_registers.BL_PWM_CNTL != 0) {
 		REG_WRITE(BL_PWM_CNTL,
 				panel_cntl->stored_backlight_registers.BL_PWM_CNTL);
@@ -119,14 +118,7 @@ static uint32_t dce_panel_cntl_hw_init(struct panel_cntl *panel_cntl)
 		REG_UPDATE(PWRSEQ_REF_DIV,
 			BL_PWM_REF_DIV,
 			panel_cntl->stored_backlight_registers.LVTMA_PWRSEQ_REF_DIV_BL_PWM_REF_DIV);
-		} else {
-			/* TODO: Note: This should not really happen since VBIOS
-			 * should have initialized PWM registers on boot.
-			 */
-			REG_WRITE(BL_PWM_CNTL, 0xC000FA00);
-			REG_WRITE(BL_PWM_PERIOD_CNTL, 0x000C0FA0);
-		}
-	} else {
+	} else if ((value != 0) && (value != 1)) {
 		panel_cntl->stored_backlight_registers.BL_PWM_CNTL =
 				REG_READ(BL_PWM_CNTL);
 		panel_cntl->stored_backlight_registers.BL_PWM_CNTL2 =
@@ -136,6 +128,12 @@ static uint32_t dce_panel_cntl_hw_init(struct panel_cntl *panel_cntl)
 
 		REG_GET(PWRSEQ_REF_DIV, BL_PWM_REF_DIV,
 				&panel_cntl->stored_backlight_registers.LVTMA_PWRSEQ_REF_DIV_BL_PWM_REF_DIV);
+	} else {
+		/* TODO: Note: This should not really happen since VBIOS
+		 * should have initialized PWM registers on boot.
+		 */
+		REG_WRITE(BL_PWM_CNTL, 0x8000FA00);
+		REG_WRITE(BL_PWM_PERIOD_CNTL, 0x000C0FA0);
 	}
 
 	// Have driver take backlight control

drivers/gpu/drm/amd/display/dc/dcn21/dcn21_hwseq.c

@@ -171,9 +171,11 @@ void dcn21_set_abm_immediate_disable(struct pipe_ctx *pipe_ctx)
 		return;
 	}
 
-	if (abm && panel_cntl)
+	if (abm && panel_cntl) {
 		dmub_abm_set_pipe(abm, otg_inst, SET_ABM_PIPE_IMMEDIATELY_DISABLE,
 				panel_cntl->inst);
+		panel_cntl->funcs->store_backlight_level(panel_cntl);
+	}
 }
 
 void dcn21_set_pipe(struct pipe_ctx *pipe_ctx)