From cb3793dec652c734e7e237b676909aa18e155ac7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= <ville.syrjala@linux.intel.com>
Date: Thu, 31 Mar 2022 14:28:18 +0300
Subject: drm/i915: Allow an arbitrary number of downclock modes
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Git-commit: 7634bef123bcf42e64acb694d545ba93b79d5b5b
Patch-mainline: v5.19-rc1
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225

Remove the "two fixed modes only" limit and grab as many
downclock modes from the EDID as we can find.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220331112822.11462-8-ville.syrjala@linux.intel.com
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
 drivers/gpu/drm/i915/display/intel_panel.c | 42 +++++++---------------
 1 file changed, 12 insertions(+), 30 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_panel.c b/drivers/gpu/drm/i915/display/intel_panel.c
index 5d08b2bf27ec..d359c8050fdc 100644
--- a/drivers/gpu/drm/i915/display/intel_panel.c
+++ b/drivers/gpu/drm/i915/display/intel_panel.c
@@ -159,42 +159,24 @@ static bool is_downclock_mode(const struct drm_display_mode *downclock_mode,
 		downclock_mode->clock < fixed_mode->clock;
 }
 
-static void intel_panel_add_edid_downclock_mode(struct intel_connector *connector)
+static void intel_panel_add_edid_downclock_modes(struct intel_connector *connector)
 {
 	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
 	const struct drm_display_mode *fixed_mode =
 		intel_panel_preferred_fixed_mode(connector);
-	struct drm_display_mode *scan, *best_mode = NULL;
-	int best_clock = fixed_mode->clock;
-
-	list_for_each_entry(scan, &connector->base.probed_modes, head) {
-		/*
-		 * If one mode has the same resolution with the fixed_panel
-		 * mode while they have the different refresh rate, it means
-		 * that the reduced downclock is found. In such
-		 * case we can set the different FPx0/1 to dynamically select
-		 * between low and high frequency.
-		 */
-		if (is_downclock_mode(scan, fixed_mode) &&
-		    scan->clock < best_clock) {
-			/*
-			 * The downclock is already found. But we
-			 * expect to find the lower downclock.
-			 */
-			best_clock = scan->clock;
-			best_mode = scan;
-		}
-	}
+	struct drm_display_mode *mode, *next;
 
-	if (!best_mode)
-		return;
+	list_for_each_entry_safe(mode, next, &connector->base.probed_modes, head) {
+		if (!is_downclock_mode(mode, fixed_mode))
+			continue;
 
-	drm_dbg_kms(&dev_priv->drm,
-		    "[CONNECTOR:%d:%s] using EDID downclock mode: " DRM_MODE_FMT "\n",
-		    connector->base.base.id, connector->base.name,
-		    DRM_MODE_ARG(best_mode));
+		drm_dbg_kms(&dev_priv->drm,
+			    "[CONNECTOR:%d:%s] using EDID downclock mode: " DRM_MODE_FMT "\n",
+			    connector->base.base.id, connector->base.name,
+			    DRM_MODE_ARG(mode));
 
-	list_move_tail(&best_mode->head, &connector->panel.fixed_modes);
+		list_move_tail(&mode->head, &connector->panel.fixed_modes);
+	}
 }
 
 static void intel_panel_add_edid_fixed_mode(struct intel_connector *connector)
@@ -243,7 +225,7 @@ void intel_panel_add_edid_fixed_modes(struct intel_connector *connector, bool ha
 {
 	intel_panel_add_edid_fixed_mode(connector);
 	if (intel_panel_preferred_fixed_mode(connector) && has_drrs)
-		intel_panel_add_edid_downclock_mode(connector);
+		intel_panel_add_edid_downclock_modes(connector);
 	intel_panel_destroy_probed_modes(connector);
 }
 
-- 
2.38.1