1 files changed, 77 insertions, 16 deletions

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 8c6ff2fa6365..b48cbde35a04 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -2190,16 +2190,72 @@ int intel_dp_dsc_compute_config(struct intel_dp *intel_dp,
 	return 0;
 }
 
-static void
+/**
+ * intel_dp_compute_config_link_bpp_limits - compute output link bpp limits
+ * @intel_dp: intel DP
+ * @crtc_state: crtc state
+ * @dsc: DSC compression mode
+ * @limits: link configuration limits
+ *
+ * Calculates the output link min, max bpp values in @limits based on the
+ * pipe bpp range, @crtc_state and @dsc mode.
+ *
+ * Returns %true in case of success.
+ */
+bool
+intel_dp_compute_config_link_bpp_limits(struct intel_dp *intel_dp,
+					const struct intel_crtc_state *crtc_state,
+					bool dsc,
+					struct link_config_limits *limits)
+{
+	struct drm_i915_private *i915 = to_i915(crtc_state->uapi.crtc->dev);
+	const struct drm_display_mode *adjusted_mode =
+		&crtc_state->hw.adjusted_mode;
+	const struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
+	const struct intel_encoder *encoder = &dp_to_dig_port(intel_dp)->base;
+	int max_link_bpp_x16;
+
+	max_link_bpp_x16 = to_bpp_x16(limits->pipe.max_bpp);
+
+	if (!dsc) {
+		max_link_bpp_x16 = rounddown(max_link_bpp_x16, to_bpp_x16(2 * 3));
+
+		if (max_link_bpp_x16 < to_bpp_x16(limits->pipe.min_bpp))
+			return false;
+
+		limits->link.min_bpp_x16 = to_bpp_x16(limits->pipe.min_bpp);
+	} else {
+		/*
+		 * TODO: set the DSC link limits already here, atm these are
+		 * initialized only later in intel_edp_dsc_compute_pipe_bpp() /
+		 * intel_dp_dsc_compute_pipe_bpp()
+		 */
+		limits->link.min_bpp_x16 = 0;
+	}
+
+	limits->link.max_bpp_x16 = max_link_bpp_x16;
+
+	drm_dbg_kms(&i915->drm,
+		    "[ENCODER:%d:%s][CRTC:%d:%s] DP link limits: pixel clock %d kHz DSC %s max lanes %d max rate %d max pipe_bpp %d max link_bpp " BPP_X16_FMT "\n",
+		    encoder->base.base.id, encoder->base.name,
+		    crtc->base.base.id, crtc->base.name,
+		    adjusted_mode->crtc_clock,
+		    dsc ? "on" : "off",
+		    limits->max_lane_count,
+		    limits->max_rate,
+		    limits->pipe.max_bpp,
+		    BPP_X16_ARGS(limits->link.max_bpp_x16));
+
+	return true;
+}
+
+static bool
 intel_dp_compute_config_limits(struct intel_dp *intel_dp,
 			       struct intel_crtc_state *crtc_state,
 			       bool respect_downstream_limits,
+			       bool dsc,
 			       struct link_config_limits *limits)
 {
-	struct drm_i915_private *i915 = dp_to_i915(intel_dp);
-	const struct drm_display_mode *adjusted_mode =
-		&crtc_state->hw.adjusted_mode;
-
 	limits->min_rate = intel_dp_common_rate(intel_dp, 0);
 	limits->max_rate = intel_dp_max_link_rate(intel_dp);
 
@@ -2225,13 +2281,10 @@ intel_dp_compute_config_limits(struct intel_dp *intel_dp,
 
 	intel_dp_adjust_compliance_config(intel_dp, crtc_state, limits);
 
-	limits->link.min_bpp_x16 = to_bpp_x16(limits->pipe.min_bpp);
-	limits->link.max_bpp_x16 = to_bpp_x16(limits->pipe.max_bpp);
-
-	drm_dbg_kms(&i915->drm, "DP link computation with max lane count %i "
-		    "max rate %d max bpp %d pixel clock %iKHz\n",
-		    limits->max_lane_count, limits->max_rate,
-		    to_bpp_int(limits->link.max_bpp_x16), adjusted_mode->crtc_clock);
+	return intel_dp_compute_config_link_bpp_limits(intel_dp,
+						       crtc_state,
+						       dsc,
+						       limits);
 }
 
 static int
@@ -2250,9 +2303,6 @@ intel_dp_compute_link_config(struct intel_encoder *encoder,
 	bool dsc_needed;
 	int ret = 0;
 
-	intel_dp_compute_config_limits(intel_dp, pipe_config,
-				       respect_downstream_limits, &limits);
-
 	if (intel_dp_need_bigjoiner(intel_dp, adjusted_mode->crtc_hdisplay,
 				    adjusted_mode->crtc_clock))
 		pipe_config->bigjoiner_pipes = GENMASK(crtc->pipe + 1, crtc->pipe);
@@ -2264,7 +2314,11 @@ intel_dp_compute_link_config(struct intel_encoder *encoder,
 	 */
 	joiner_needs_dsc = DISPLAY_VER(i915) < 13 && pipe_config->bigjoiner_pipes;
 
-	dsc_needed = joiner_needs_dsc || intel_dp->force_dsc_en;
+	dsc_needed = joiner_needs_dsc || intel_dp->force_dsc_en ||
+		     !intel_dp_compute_config_limits(intel_dp, pipe_config,
+						     respect_downstream_limits,
+						     false,
+						     &limits);
 
 	if (!dsc_needed) {
 		/*
@@ -2281,6 +2335,13 @@ intel_dp_compute_link_config(struct intel_encoder *encoder,
 		drm_dbg_kms(&i915->drm, "Try DSC (fallback=%s, joiner=%s, force=%s)\n",
 			    str_yes_no(ret), str_yes_no(joiner_needs_dsc),
 			    str_yes_no(intel_dp->force_dsc_en));
+
+		if (!intel_dp_compute_config_limits(intel_dp, pipe_config,
+						    respect_downstream_limits,
+						    true,
+						    &limits))
+			return -EINVAL;
+
 		ret = intel_dp_dsc_compute_config(intel_dp, pipe_config,
 						  conn_state, &limits, 64, true);
 		if (ret < 0)