diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
index 0ec212ead9f02..972b8a5588ec2 100644
--- a/drivers/gpu/drm/i915/display/intel_ddi.c
+++ b/drivers/gpu/drm/i915/display/intel_ddi.c
@@ -2539,7 +2539,9 @@ static void mtl_ddi_pre_enable_dp(struct intel_atomic_state *state,
 
 	intel_dp_configure_protocol_converter(intel_dp, crtc_state);
 	if (!is_mst)
-		intel_dp_sink_set_decompression_state(intel_dp, crtc_state, true);
+		intel_dp_sink_enable_decompression(state,
+						   to_intel_connector(conn_state->connector),
+						   crtc_state);
 
 	/*
 	 * DDI FEC: "anticipates enabling FEC encoding sets the FEC_READY bit
@@ -2692,7 +2694,9 @@ static void tgl_ddi_pre_enable_dp(struct intel_atomic_state *state,
 
 	intel_dp_configure_protocol_converter(intel_dp, crtc_state);
 	if (!is_mst)
-		intel_dp_sink_set_decompression_state(intel_dp, crtc_state, true);
+		intel_dp_sink_enable_decompression(state,
+						   to_intel_connector(conn_state->connector),
+						   crtc_state);
 	/*
 	 * DDI FEC: "anticipates enabling FEC encoding sets the FEC_READY bit
 	 * in the FEC_CONFIGURATION register to 1 before initiating link
@@ -2773,8 +2777,9 @@ static void hsw_ddi_pre_enable_dp(struct intel_atomic_state *state,
 		intel_dp_set_power(intel_dp, DP_SET_POWER_D0);
 	intel_dp_configure_protocol_converter(intel_dp, crtc_state);
 	if (!is_mst)
-		intel_dp_sink_set_decompression_state(intel_dp, crtc_state,
-						      true);
+		intel_dp_sink_enable_decompression(state,
+						   to_intel_connector(conn_state->connector),
+						   crtc_state);
 	intel_dp_sink_set_fec_ready(intel_dp, crtc_state, true);
 	intel_dp_start_link_train(intel_dp, crtc_state);
 	if ((port != PORT_A || DISPLAY_VER(dev_priv) >= 9) &&
@@ -3354,6 +3359,8 @@ static void intel_disable_ddi_dp(struct intel_atomic_state *state,
 				 const struct drm_connector_state *old_conn_state)
 {
 	struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
+	struct intel_connector *connector =
+		to_intel_connector(old_conn_state->connector);
 
 	intel_dp->link_trained = false;
 
@@ -3362,8 +3369,8 @@ static void intel_disable_ddi_dp(struct intel_atomic_state *state,
 	intel_psr_disable(intel_dp, old_crtc_state);
 	intel_edp_backlight_off(old_conn_state);
 	/* Disable the decompression in DP Sink */
-	intel_dp_sink_set_decompression_state(intel_dp, old_crtc_state,
-					      false);
+	intel_dp_sink_disable_decompression(state,
+					    connector, old_crtc_state);
 	/* Disable Ignore_MSA bit in DP Sink */
 	intel_dp_sink_set_msa_timing_par_ignore_state(intel_dp, old_crtc_state,
 						      false);
diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index e4f674192f3b7..0cdb4d176a8f9 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -2937,24 +2937,94 @@ static bool downstream_hpd_needs_d0(struct intel_dp *intel_dp)
 		intel_dp->downstream_ports[0] & DP_DS_PORT_HPD;
 }
 
-void intel_dp_sink_set_decompression_state(struct intel_dp *intel_dp,
-					   const struct intel_crtc_state *crtc_state,
-					   bool enable)
+static int
+write_dsc_decompression_flag(struct drm_dp_aux *aux, u8 flag, bool set)
 {
-	struct drm_i915_private *i915 = dp_to_i915(intel_dp);
-	int ret;
+	int err;
+	u8 val;
 
-	if (!crtc_state->dsc.compression_enable)
-		return;
+	err = drm_dp_dpcd_readb(aux, DP_DSC_ENABLE, &val);
+	if (err < 0)
+		return err;
 
-	ret = drm_dp_dpcd_writeb(&intel_dp->aux, DP_DSC_ENABLE,
-				 enable ? DP_DECOMPRESSION_EN : 0);
-	if (ret < 0)
+	if (set)
+		val |= flag;
+	else
+		val &= ~flag;
+
+	return drm_dp_dpcd_writeb(aux, DP_DSC_ENABLE, val);
+}
+
+static void
+intel_dp_sink_set_dsc_decompression(struct intel_connector *connector,
+				    bool enable)
+{
+	struct drm_i915_private *i915 = to_i915(connector->base.dev);
+
+	if (write_dsc_decompression_flag(connector->dp.dsc_decompression_aux,
+					 DP_DECOMPRESSION_EN, enable) < 0)
 		drm_dbg_kms(&i915->drm,
 			    "Failed to %s sink decompression state\n",
 			    str_enable_disable(enable));
 }
 
+/**
+ * intel_dp_sink_enable_decompression - Enable DSC decompression in sink/last branch device
+ * @state: atomic state
+ * @connector: connector to enable the decompression for
+ * @new_crtc_state: new state for the CRTC driving @connector
+ *
+ * Enable the DSC decompression if required in the %DP_DSC_ENABLE DPCD
+ * register of the appropriate sink/branch device. On SST this is always the
+ * sink device, whereas on MST based on each device's DSC capabilities it's
+ * either the last branch device (enabling decompression in it) or both the
+ * last branch device (enabling passthrough in it) and the sink device
+ * (enabling decompression in it).
+ */
+void intel_dp_sink_enable_decompression(struct intel_atomic_state *state,
+					struct intel_connector *connector,
+					const struct intel_crtc_state *new_crtc_state)
+{
+	struct drm_i915_private *i915 = to_i915(state->base.dev);
+
+	if (!new_crtc_state->dsc.compression_enable)
+		return;
+
+	if (drm_WARN_ON(&i915->drm,
+			!connector->dp.dsc_decompression_aux))
+		return;
+
+	/* TODO: Enable passthrough in the MST last branch device if needed. */
+	intel_dp_sink_set_dsc_decompression(connector, true);
+}
+
+/**
+ * intel_dp_sink_disable_decompression - Disable DSC decompression in sink/last branch device
+ * @state: atomic state
+ * @connector: connector to disable the decompression for
+ * @old_crtc_state: old state for the CRTC driving @connector
+ *
+ * Disable the DSC decompression if required in the %DP_DSC_ENABLE DPCD
+ * register of the appropriate sink/branch device, corresponding to the
+ * sequence in intel_dp_sink_enable_decompression().
+ */
+void intel_dp_sink_disable_decompression(struct intel_atomic_state *state,
+					 struct intel_connector *connector,
+					 const struct intel_crtc_state *old_crtc_state)
+{
+	struct drm_i915_private *i915 = to_i915(state->base.dev);
+
+	if (!old_crtc_state->dsc.compression_enable)
+		return;
+
+	if (drm_WARN_ON(&i915->drm,
+			!connector->dp.dsc_decompression_aux))
+		return;
+
+	intel_dp_sink_set_dsc_decompression(connector, false);
+	/* TODO: Disable passthrough in the MST last branch device if needed. */
+}
+
 static void
 intel_edp_init_source_oui(struct intel_dp *intel_dp, bool careful)
 {
diff --git a/drivers/gpu/drm/i915/display/intel_dp.h b/drivers/gpu/drm/i915/display/intel_dp.h
index 2080575fef69a..7cc23d846dfbf 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.h
+++ b/drivers/gpu/drm/i915/display/intel_dp.h
@@ -57,9 +57,12 @@ int intel_dp_retrain_link(struct intel_encoder *encoder,
 void intel_dp_set_power(struct intel_dp *intel_dp, u8 mode);
 void intel_dp_configure_protocol_converter(struct intel_dp *intel_dp,
 					   const struct intel_crtc_state *crtc_state);
-void intel_dp_sink_set_decompression_state(struct intel_dp *intel_dp,
-					   const struct intel_crtc_state *crtc_state,
-					   bool enable);
+void intel_dp_sink_enable_decompression(struct intel_atomic_state *state,
+					struct intel_connector *connector,
+					const struct intel_crtc_state *new_crtc_state);
+void intel_dp_sink_disable_decompression(struct intel_atomic_state *state,
+					 struct intel_connector *connector,
+					 const struct intel_crtc_state *old_crtc_state);
 void intel_dp_encoder_suspend(struct intel_encoder *intel_encoder);
 void intel_dp_encoder_shutdown(struct intel_encoder *intel_encoder);
 void intel_dp_encoder_flush_work(struct drm_encoder *encoder);
diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c
index f970e25f57fec..355a573c97930 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
@@ -753,7 +753,7 @@ static void intel_mst_disable_dp(struct intel_atomic_state *state,
 		 * TODO: disable decompression for all streams/in any MST ports, not
 		 * only in the first downstream branch device.
 		 */
-		intel_dp_sink_set_decompression_state(intel_dp, old_crtc_state, false);
+		intel_dp_sink_disable_decompression(state, connector, old_crtc_state);
 }
 
 static void intel_mst_post_disable_dp(struct intel_atomic_state *state,
@@ -913,7 +913,7 @@ static void intel_mst_pre_enable_dp(struct intel_atomic_state *state,
 		 * TODO: enable decompression for all streams/in any MST ports, not
 		 * only in the first downstream branch device.
 		 */
-		intel_dp_sink_set_decompression_state(intel_dp, pipe_config, true);
+		intel_dp_sink_enable_decompression(state, connector, pipe_config);
 		dig_port->base.pre_enable(state, &dig_port->base,
 						pipe_config, NULL);
 	}
