drm/i915/dp: Make sure the DSC PPS SDP is disabled whenever DSC is disabled

Atm the DSC PPS SDP will stay enabled after enabling and disabling DSC.
This leaves an output blank after switching off DSC on it. Make sure the
SDP is disabled for an uncompressed output.

v2:
- Disable the SDP already during output disabling. (Ville)

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231030155843.2251023-17-imre.deak@intel.com

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

@@ -4069,7 +4069,10 @@ void intel_dp_set_infoframes(struct intel_encoder *encoder,
 			 VIDEO_DIP_ENABLE_SPD_HSW | VIDEO_DIP_ENABLE_DRM_GLK;
 	u32 val = intel_de_read(dev_priv, reg) & ~dip_enable;
 
-	/* TODO: Add DSC case (DIP_ENABLE_PPS) */
+	/* TODO: Sanitize DSC enabling wrt. intel_dsc_dp_pps_write(). */
+	if (!enable && HAS_DSC(dev_priv))
+		val &= ~VDIP_ENABLE_PPS;
+
 	/* When PSR is enabled, this routine doesn't disable VSC DIP */
 	if (!crtc_state->has_psr)
 		val &= ~VIDEO_DIP_ENABLE_VSC_HSW;

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

@@ -746,9 +746,8 @@ static void intel_mst_post_disable_dp(struct intel_atomic_state *state,
 	 * BSpec 4287: disable DIP after the transcoder is disabled and before
 	 * the transcoder clock select is set to none.
 	 */
-	if (last_mst_stream)
-		intel_dp_set_infoframes(&dig_port->base, false,
-					old_crtc_state, NULL);
+	intel_dp_set_infoframes(&dig_port->base, false,
+				old_crtc_state, NULL);
 	/*
 	 * From TGL spec: "If multi-stream slave transcoder: Configure
 	 * Transcoder Clock Select to direct no clock to the transcoder"