drm/i915/tgl/dsi: Enable blanking packets during BLLP for video mode

Blanking packet bit will control whether the transcoder allows the link
to enter the LP state during BLLP regions (assuming there is enough time),
or whether it will keep the link in the HS state with a Blanking Packet

Signed-off-by: Vandita Kulkarni <[e-mail]>
Reviewed-by: Uma Shankar <[e-mail]>
Signed-off-by: Uma Shankar <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

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

···
 			break;
 		}
 
+		if (INTEL_GEN(dev_priv) >= 12) {
+			if (is_vid_mode(intel_dsi))
+				tmp |= BLANKING_PACKET_ENABLE;
+		}
+
 		/* program DSI operation mode */
 		if (is_vid_mode(intel_dsi)) {
 			tmp &= ~OP_MODE_MASK;

drivers/gpu/drm/i915/i915_reg.h

···
 #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  S3D_ORIENTATION_LANDSCAPE	(1 << 1)
 #define  EOTP_DISABLED			(1 << 0)