drm/i915/dsi: Fill BLLPs with blanking packets if requested

TGL/ADL DSI can be configured to fill all BLLPs with blanking
packets. Currently we enable that always, but the VBT actually
tells us whether this is desired or not. Hook that up.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patch.msgid.link/20260326111814.9800-5-ville.syrjala@linux.intel.com
Reviewed-by: Jani Nikula <jani.nikula@intel.com>

Author: vsyrjala

drivers/gpu/drm/i915/display/icl_dsi.c

@@ -765,10 +765,11 @@ gen11_dsi_configure_transcoder(struct intel_encoder *encoder,
 			}
 		}
 
-		if (DISPLAY_VER(display) >= 12) {
-			if (is_vid_mode(intel_dsi))
-				tmp |= BLANKING_PACKET_ENABLE;
-		}
+		if (DISPLAY_VER(display) >= 12 &&
+		    is_vid_mode(intel_dsi) && intel_dsi->blanking_pkt)
+			tmp |= BLANKING_PACKET_ENABLE;
+		else
+			tmp &= ~BLANKING_PACKET_ENABLE;
 
 		/* program DSI operation mode */
 		if (is_vid_mode(intel_dsi)) {

drivers/gpu/drm/i915/display/icl_dsi_regs.h

@@ -232,7 +232,7 @@
 #define  CALIBRATION_DISABLED		(0x0 << 4)
 #define  CALIBRATION_ENABLED_INITIAL_ONLY	(0x2 << 4)
 #define  CALIBRATION_ENABLED_INITIAL_PERIODIC	(0x3 << 4)
-#define  BLANKING_PACKET_ENABLE		(1 << 2)
+#define  BLANKING_PACKET_ENABLE		(1 << 2) /* tgl+ */
 #define  S3D_ORIENTATION_LANDSCAPE	(1 << 1)
 #define  EOTP_DISABLED			(1 << 0)
 

drivers/gpu/drm/i915/display/intel_dsi.h

@@ -80,6 +80,7 @@ struct intel_dsi {
 	/* NON_BURST_SYNC_PULSE, NON_BURST_SYNC_EVENTS, or BURST_MODE */
 	int video_mode;
 
+	bool blanking_pkt;
 	bool eot_pkt;
 	bool clock_stop;
 

drivers/gpu/drm/i915/display/intel_dsi_vbt.c

@@ -718,6 +718,7 @@ void intel_dsi_log_params(struct intel_dsi *intel_dsi)
 		   "burst" : "<unknown>");
 	drm_printf(&p, "Burst mode ratio %d\n", intel_dsi->burst_mode_ratio);
 	drm_printf(&p, "Reset timer %d\n", intel_dsi->rst_timer_val);
+	drm_printf(&p, "Blanking packets during BLLP %s\n", str_enabled_disabled(intel_dsi->blanking_pkt));
 	drm_printf(&p, "EoT packet %s\n", str_enabled_disabled(intel_dsi->eot_pkt));
 	drm_printf(&p, "Clock stop during BLLP %s\n", str_enabled_disabled(intel_dsi->clock_stop));
 	drm_printf(&p, "Mode %s\n", intel_dsi->operation_mode ? "command" : "video");
@@ -770,6 +771,7 @@ bool intel_dsi_vbt_init(struct intel_dsi *intel_dsi, u16 panel_id)
 
 	drm_dbg_kms(display->drm, "\n");
 
+	intel_dsi->blanking_pkt = mipi_config->blanking_packets_during_bllp;
 	intel_dsi->eot_pkt = !mipi_config->eot_pkt_disabled;
 	intel_dsi->clock_stop = mipi_config->enable_clk_stop;
 	intel_dsi->lane_count = mipi_config->lane_cnt + 1;