drm/i915/edp: Allow alternate fixed mode for eDP if available.

Some fixed resolution panels actually support more than one mode,
with the only thing different being the refresh rate.  Having this
alternate mode available to us is desirable, because it allows us to
test PSR on panels whose setup time at the preferred mode is too long.
With this patch we allow the use of the alternate mode if it's
available and it was specifically requested.

v2 and v3: Rebase
v4: * Fix up some leaky mode stuff (Chris)
    * Rebase
v5: * Fix a NULL pointer derefrence (David Weinehall)
v6: * Whitespace / spelling / checkpatch clean-up; no functional
      change. (David)
    * Rebase

Cc: David Weinehall <david.weinehall@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NDavid Weinehall <david.weinehall@linux.intel.com>
Signed-off-by: NJim Bride <jim.bride@linux.intel.com>
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1502308133-26892-1-git-send-email-jim.bride@linux.intel.com

drivers/gpu/drm/i915/intel_dp.c

@@ -1619,6 +1619,23 @@ static int intel_dp_compute_bpp(struct intel_dp *intel_dp,
 	return bpp;
 }
 
+static bool intel_edp_compare_alt_mode(struct drm_display_mode *m1,
+				       struct drm_display_mode *m2)
+{
+	bool bres = false;
+
+	if (m1 && m2)
+		bres = (m1->hdisplay == m2->hdisplay &&
+			m1->hsync_start == m2->hsync_start &&
+			m1->hsync_end == m2->hsync_end &&
+			m1->htotal == m2->htotal &&
+			m1->vdisplay == m2->vdisplay &&
+			m1->vsync_start == m2->vsync_start &&
+			m1->vsync_end == m2->vsync_end &&
+			m1->vtotal == m2->vtotal);
+	return bres;
+}
+
 bool
 intel_dp_compute_config(struct intel_encoder *encoder,
 			struct intel_crtc_state *pipe_config,
@@ -1665,8 +1682,16 @@ intel_dp_compute_config(struct intel_encoder *encoder,
 		pipe_config->has_audio = intel_conn_state->force_audio == HDMI_AUDIO_ON;
 
 	if (is_edp(intel_dp) && intel_connector->panel.fixed_mode) {
-		intel_fixed_panel_mode(intel_connector->panel.fixed_mode,
-				       adjusted_mode);
+		struct drm_display_mode *panel_mode =
+			intel_connector->panel.alt_fixed_mode;
+		struct drm_display_mode *req_mode = &pipe_config->base.mode;
+
+		if (!intel_edp_compare_alt_mode(req_mode, panel_mode))
+			panel_mode = intel_connector->panel.fixed_mode;
+
+		drm_mode_debug_printmodeline(panel_mode);
+
+		intel_fixed_panel_mode(panel_mode, adjusted_mode);
 
 		if (INTEL_GEN(dev_priv) >= 9) {
 			int ret;
@@ -5794,6 +5819,7 @@ static bool intel_edp_init_connector(struct intel_dp *intel_dp,
 	struct drm_device *dev = intel_encoder->base.dev;
 	struct drm_i915_private *dev_priv = to_i915(dev);
 	struct drm_display_mode *fixed_mode = NULL;
+	struct drm_display_mode *alt_fixed_mode = NULL;
 	struct drm_display_mode *downclock_mode = NULL;
 	bool has_dpcd;
 	struct drm_display_mode *scan;
@@ -5849,13 +5875,14 @@ static bool intel_edp_init_connector(struct intel_dp *intel_dp,
 	}
 	intel_connector->edid = edid;
 
-	/* prefer fixed mode from EDID if available */
+	/* prefer fixed mode from EDID if available, save an alt mode also */
 	list_for_each_entry(scan, &connector->probed_modes, head) {
 		if ((scan->type & DRM_MODE_TYPE_PREFERRED)) {
 			fixed_mode = drm_mode_duplicate(dev, scan);
 			downclock_mode = intel_dp_drrs_init(
 						intel_connector, fixed_mode);
-			break;
+		} else if (!alt_fixed_mode) {
+			alt_fixed_mode = drm_mode_duplicate(dev, scan);
 		}
 	}
 
@@ -5892,7 +5919,8 @@ static bool intel_edp_init_connector(struct intel_dp *intel_dp,
 			      pipe_name(pipe));
 	}
 
-	intel_panel_init(&intel_connector->panel, fixed_mode, downclock_mode);
+	intel_panel_init(&intel_connector->panel, fixed_mode, alt_fixed_mode,
+			 downclock_mode);
 	intel_connector->panel.backlight.power = intel_edp_backlight_power;
 	intel_panel_setup_backlight(connector, pipe);
 

drivers/gpu/drm/i915/intel_drv.h

@@ -265,6 +265,7 @@ struct intel_encoder {
 
 struct intel_panel {
 	struct drm_display_mode *fixed_mode;
+	struct drm_display_mode *alt_fixed_mode;
 	struct drm_display_mode *downclock_mode;
 
 	/* backlight */
@@ -1678,6 +1679,7 @@ void intel_overlay_reset(struct drm_i915_private *dev_priv);
 /* intel_panel.c */
 int intel_panel_init(struct intel_panel *panel,
 		     struct drm_display_mode *fixed_mode,
+		     struct drm_display_mode *alt_fixed_mode,
 		     struct drm_display_mode *downclock_mode);
 void intel_panel_fini(struct intel_panel *panel);
 void intel_fixed_panel_mode(const struct drm_display_mode *fixed_mode,

drivers/gpu/drm/i915/intel_dsi.c

@@ -1849,7 +1849,7 @@ void intel_dsi_init(struct drm_i915_private *dev_priv)
 	connector->display_info.width_mm = fixed_mode->width_mm;
 	connector->display_info.height_mm = fixed_mode->height_mm;
 
-	intel_panel_init(&intel_connector->panel, fixed_mode, NULL);
+	intel_panel_init(&intel_connector->panel, fixed_mode, NULL, NULL);
 	intel_panel_setup_backlight(connector, INVALID_PIPE);
 
 	intel_dsi_add_properties(intel_connector);

drivers/gpu/drm/i915/intel_dvo.c

@@ -552,7 +552,7 @@ void intel_dvo_init(struct drm_i915_private *dev_priv)
 			 */
 			intel_panel_init(&intel_connector->panel,
 					 intel_dvo_get_current_mode(connector),
-					 NULL);
+					 NULL, NULL);
 			intel_dvo->panel_wants_dither = true;
 		}
 

drivers/gpu/drm/i915/intel_lvds.c

@@ -1138,7 +1138,8 @@ void intel_lvds_init(struct drm_i915_private *dev_priv)
 out:
 	mutex_unlock(&dev->mode_config.mutex);
 
-	intel_panel_init(&intel_connector->panel, fixed_mode, downclock_mode);
+	intel_panel_init(&intel_connector->panel, fixed_mode, NULL,
+			 downclock_mode);
 	intel_panel_setup_backlight(connector, INVALID_PIPE);
 
 	lvds_encoder->is_dual_link = compute_is_dual_link_lvds(lvds_encoder);

drivers/gpu/drm/i915/intel_panel.c

@@ -1920,11 +1920,13 @@ intel_panel_init_backlight_funcs(struct intel_panel *panel)
 
 int intel_panel_init(struct intel_panel *panel,
 		     struct drm_display_mode *fixed_mode,
+		     struct drm_display_mode *alt_fixed_mode,
 		     struct drm_display_mode *downclock_mode)
 {
 	intel_panel_init_backlight_funcs(panel);
 
 	panel->fixed_mode = fixed_mode;
+	panel->alt_fixed_mode = alt_fixed_mode;
 	panel->downclock_mode = downclock_mode;
 
 	return 0;
@@ -1938,6 +1940,10 @@ void intel_panel_fini(struct intel_panel *panel)
 	if (panel->fixed_mode)
 		drm_mode_destroy(intel_connector->base.dev, panel->fixed_mode);
 
+	if (panel->alt_fixed_mode)
+		drm_mode_destroy(intel_connector->base.dev,
+				panel->alt_fixed_mode);
+
 	if (panel->downclock_mode)
 		drm_mode_destroy(intel_connector->base.dev,
 				panel->downclock_mode);