[Intel-gfx] [PATCH] drm/i915: Allow more varied alternate fixed modes for panels

[Ville Syrjala <ville.syrjala@linux.intel.com>]

From: Ville Syrjälä <ville.syrjala@linux.intel.com>

On some systems the panel reports alternate modes with
different blanking periods. If the EDID reports them and VBT
doesn't tell us otherwise then I can't really see why they
should be rejected. So allow their use for the purposes of
static DRRS.

For seamless DRRS we still require a much more exact match
of course. But that logic only kicks in when selecting the
downclock mode (or in the future when determining whether
we can do a seamless refresh rate change due to a user
modeset).

Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/6374
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
---
 drivers/gpu/drm/i915/display/intel_panel.c | 25 ++++++----------------
 1 file changed, 6 insertions(+), 19 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_panel.c b/drivers/gpu/drm/i915/display/intel_panel.c
index 237a40623dd7..cb44984bb9a2 100644
--- a/drivers/gpu/drm/i915/display/intel_panel.c
+++ b/drivers/gpu/drm/i915/display/intel_panel.c
@@ -81,15 +81,14 @@ static bool is_alt_drrs_mode(const struct drm_display_mode *mode,
 		mode->clock != preferred_mode->clock;
 }
 
-static bool is_alt_vrr_mode(const struct drm_display_mode *mode,
-			    const struct drm_display_mode *preferred_mode)
+static bool is_alt_fixed_mode(const struct drm_display_mode *mode,
+			      const struct drm_display_mode *preferred_mode)
 {
 	return drm_mode_match(mode, preferred_mode,
 			      DRM_MODE_MATCH_FLAGS |
 			      DRM_MODE_MATCH_3D_FLAGS) &&
 		mode->hdisplay == preferred_mode->hdisplay &&
-		mode->vdisplay == preferred_mode->vdisplay &&
-		mode->clock != preferred_mode->clock;
+		mode->vdisplay == preferred_mode->vdisplay;
 }
 
 const struct drm_display_mode *
@@ -172,19 +171,7 @@ int intel_panel_compute_config(struct intel_connector *connector,
 	return 0;
 }
 
-static bool is_alt_fixed_mode(const struct drm_display_mode *mode,
-			      const struct drm_display_mode *preferred_mode,
-			      bool has_vrr)
-{
-	/* is_alt_drrs_mode() is a subset of is_alt_vrr_mode() */
-	if (has_vrr)
-		return is_alt_vrr_mode(mode, preferred_mode);
-	else
-		return is_alt_drrs_mode(mode, preferred_mode);
-}
-
-static void intel_panel_add_edid_alt_fixed_modes(struct intel_connector *connector,
-						 bool has_vrr)
+static void intel_panel_add_edid_alt_fixed_modes(struct intel_connector *connector)
 {
 	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
 	const struct drm_display_mode *preferred_mode =
@@ -192,7 +179,7 @@ static void intel_panel_add_edid_alt_fixed_modes(struct intel_connector *connect
 	struct drm_display_mode *mode, *next;
 
 	list_for_each_entry_safe(mode, next, &connector->base.probed_modes, head) {
-		if (!is_alt_fixed_mode(mode, preferred_mode, has_vrr))
+		if (!is_alt_fixed_mode(mode, preferred_mode))
 			continue;
 
 		drm_dbg_kms(&dev_priv->drm,
@@ -255,7 +242,7 @@ void intel_panel_add_edid_fixed_modes(struct intel_connector *connector,
 {
 	intel_panel_add_edid_preferred_mode(connector);
 	if (intel_panel_preferred_fixed_mode(connector) && (has_drrs || has_vrr))
-		intel_panel_add_edid_alt_fixed_modes(connector, has_vrr);
+		intel_panel_add_edid_alt_fixed_modes(connector);
 	intel_panel_destroy_probed_modes(connector);
 }
 
-- 
2.35.1