drm/i915: Introduce intel_panel_compute_config()

Let's introduce a compute_config() helper for fixed mode panels.
For now all it does is the fixed_mode->adjusted_mode copy.

Note that with sDVO we have to ask the external encoder chip
to spit out our actual display timings for us, so the fixed_mode
to adjusted_mode copy done by intel_panel_compute_config() is
redundant, but we still want to use it to do other checks for us
later. We'll be fine so long as we only call it before
intel_sdvo_get_preferred_input_mode() overwrites adjusted_mode
with the timings from the encoder.

v2: Use intel_panel_compute_config() with sDVO

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210927185207.13620-1-ville.syrjala@linux.intel.com
Reviewed-by: Jani Nikula <jani.nikula@intel.com>

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

@@ -1672,14 +1672,15 @@ static int gen11_dsi_compute_config(struct intel_encoder *encoder,
 	struct intel_dsi *intel_dsi = container_of(encoder, struct intel_dsi,
 						   base);
 	struct intel_connector *intel_connector = intel_dsi->attached_connector;
-	const struct drm_display_mode *fixed_mode =
-		intel_connector->panel.fixed_mode;
 	struct drm_display_mode *adjusted_mode =
 		&pipe_config->hw.adjusted_mode;
 	int ret;
 
 	pipe_config->output_format = INTEL_OUTPUT_FORMAT_RGB;
-	intel_panel_fixed_mode(fixed_mode, adjusted_mode);
+
+	ret = intel_panel_compute_config(intel_connector, adjusted_mode);
+	if (ret)
+		return ret;
 
 	ret = intel_panel_fitting(pipe_config, conn_state);
 	if (ret)

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

@@ -1757,8 +1757,9 @@ intel_dp_compute_config(struct intel_encoder *encoder,
 		pipe_config->has_audio = intel_conn_state->force_audio == HDMI_AUDIO_ON;
 
 	if (intel_dp_is_edp(intel_dp) && intel_connector->panel.fixed_mode) {
-		intel_panel_fixed_mode(intel_connector->panel.fixed_mode,
-				       adjusted_mode);
+		ret = intel_panel_compute_config(intel_connector, adjusted_mode);
+		if (ret)
+			return ret;
 
 		ret = intel_panel_fitting(pipe_config, conn_state);
 		if (ret)

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

@@ -256,6 +256,7 @@ static int intel_dvo_compute_config(struct intel_encoder *encoder,
 				    struct drm_connector_state *conn_state)
 {
 	struct intel_dvo *intel_dvo = enc_to_dvo(encoder);
+	struct intel_connector *connector = to_intel_connector(conn_state->connector);
 	const struct drm_display_mode *fixed_mode =
 		intel_dvo->attached_connector->panel.fixed_mode;
 	struct drm_display_mode *adjusted_mode = &pipe_config->hw.adjusted_mode;
@@ -266,8 +267,13 @@ static int intel_dvo_compute_config(struct intel_encoder *encoder,
 	 * with the panel scaling set up to source from the H/VDisplay
 	 * of the original mode.
 	 */
-	if (fixed_mode)
-		intel_panel_fixed_mode(fixed_mode, adjusted_mode);
+	if (fixed_mode) {
+		int ret;
+
+		ret = intel_panel_compute_config(connector, adjusted_mode);
+		if (ret)
+			return ret;
+	}
 
 	if (adjusted_mode->flags & DRM_MODE_FLAG_DBLSCAN)
 		return -EINVAL;

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

@@ -444,8 +444,9 @@ static int intel_lvds_compute_config(struct intel_encoder *intel_encoder,
 	 * with the panel scaling set up to source from the H/VDisplay
 	 * of the original mode.
 	 */
-	intel_panel_fixed_mode(intel_connector->panel.fixed_mode,
-			       adjusted_mode);
+	ret = intel_panel_compute_config(intel_connector, adjusted_mode);
+	if (ret)
+		return ret;
 
 	if (adjusted_mode->flags & DRM_MODE_FLAG_DBLSCAN)
 		return -EINVAL;

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

@@ -45,12 +45,19 @@ bool intel_panel_use_ssc(struct drm_i915_private *i915)
 		&& !(i915->quirks & QUIRK_LVDS_SSC_DISABLE);
 }
 
-void intel_panel_fixed_mode(const struct drm_display_mode *fixed_mode,
-			    struct drm_display_mode *adjusted_mode)
+int intel_panel_compute_config(struct intel_connector *connector,
+			       struct drm_display_mode *adjusted_mode)
 {
+	const struct drm_display_mode *fixed_mode = connector->panel.fixed_mode;
+
+	if (!fixed_mode)
+		return 0;
+
 	drm_mode_copy(adjusted_mode, fixed_mode);
 
 	drm_mode_set_crtcinfo(adjusted_mode, 0);
+
+	return 0;
 }
 
 static bool is_downclock_mode(const struct drm_display_mode *downclock_mode,

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

@@ -31,6 +31,8 @@ intel_panel_mode_valid(struct intel_connector *connector,
 		       const struct drm_display_mode *mode);
 int intel_panel_fitting(struct intel_crtc_state *crtc_state,
 			const struct drm_connector_state *conn_state);
+int intel_panel_compute_config(struct intel_connector *connector,
+			       struct drm_display_mode *adjusted_mode);
 struct drm_display_mode *
 intel_panel_edid_downclock_mode(struct intel_connector *connector,
 				const struct drm_display_mode *fixed_mode);

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

@@ -1335,6 +1335,13 @@ static int intel_sdvo_compute_config(struct intel_encoder *encoder,
 							   adjusted_mode);
 		pipe_config->sdvo_tv_clock = true;
 	} else if (IS_LVDS(intel_sdvo_connector)) {
+		int ret;
+
+		ret = intel_panel_compute_config(&intel_sdvo_connector->base,
+						 adjusted_mode);
+		if (ret)
+			return ret;
+
 		if (!intel_sdvo_set_output_timings_from_mode(intel_sdvo,
 							     intel_sdvo_connector->base.panel.fixed_mode))
 			return -EINVAL;

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

@@ -279,7 +279,9 @@ static int intel_dsi_compute_config(struct intel_encoder *encoder,
 	pipe_config->output_format = INTEL_OUTPUT_FORMAT_RGB;
 
 	if (fixed_mode) {
-		intel_panel_fixed_mode(fixed_mode, adjusted_mode);
+		ret = intel_panel_compute_config(intel_connector, adjusted_mode);
+		if (ret)
+			return ret;
 
 		ret = intel_panel_fitting(pipe_config, conn_state);
 		if (ret)