drm/i915: Allow an arbitrary number of downclock modes

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>

diff --git a/drivers/gpu/drm/i915/display/intel_panel.c b/drivers/gpu/drm/i915/display/intel_panel.c
index 5d08b2bf27ec006fad3fc4211e4160825c57a9f0..d359c8050fdcbfb8445f0ecb03e10a1531dd310a 100644 (file)
--- 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);
 }